00:00:04 Neil Donnelly
We are seeing that if a system is way oversized, we do not get to operate that system at it’s peak efficiency.
00:00:13 Charlie Simek
If we have a really good understanding of exactly what a building is using, then we can go forward and design a system that’s matching up with that super well.
00:00:25 Michelle Moran
Welcome to Building Well: Sustainable Homes, Equitable Communities— your new podcast from New Ecology. Join us as we explore real life stories from key players in green building and community development.
00:00:37
We’ll examine exciting new innovations, highlighting practical solutions for creating more affordable, healthier, more resilient equitable communities. We’re building well together.
00:00:50 Molly Craft
This episode was made possible by the Mass Save Community Education Grant.
00:00:58 Alina
Welcome to the Building well podcast. Your source for information about sustainable buildings and equitable communities. I’m your host, Alina Michelewicz, and this is my co-host, Michelle.
00:01:08 MM
Hello
00:01:09 Alina M
Today we’re interviewing Charlie Simek and Neil Donnelly about their recent research on domestic hot water system efficiency. I’ve had an extra cup of coffee this morning and only sugar for breakfast.
00:01:20
So I’m determined to learn how hot water systems work, and so let’s just get right into it. Welcome Neil and Charlie.
00:01:28 Neil D
Thanks.
00:01:28 Charlie S
Thank you.
00:01:29 Alina M
Could you guys start by introducing yourselves—your names, pronouns, titles, what you do here at New Ecology.
00:01:36 Neil D
Yeah. My name is Neil Donnelly (he/him), and I’m a Senior Energy Engineer, joined in 2013.
00:01:44 Charlie S
I’m Charlie Simek (He/Him). I’m an Energy Engineer. I’ve worked very closely with Neil and been working here for almost three years now and did some internships in college and that’s how I joined New Ecology.
00:01:56 Alina M
Cool. Thanks. What kind of projects do you guys work on at New Ecology?
00:02:04 Neil D
We’ve been creating our decarbonization audit system over the last couple of years, so that’s a big shift in our audit focus with really the goal of moving these buildings to a zero-carbon operation in the future.
00:02:22 Alina M
What’s causing next shift?
00:02:24 Neil D
In Massachusetts, there are policy changes. We have BERDO in Boston, and that is really pushing the conversation with a lot of building owners and operators that they’re now recognizing that they do need to electrify all their systems, and that’s how they’re going to get to a zero-carbon operation in the future.
00:02:44 Alina M
Cool. Nice. And what kinds of stuff do you do Charlie?
00:02:47 Charlie S
So I also work on the decarbonization audits, but I also work on the Electrify Cambridge program, which essentially does a very light touch decarbonization audit. It’s run by the city of Cambridge and provides audits free to any residential buildings in the city that are looking to plan ahead and deal with these similar regulations to what’s coming in Boston.
Cambridge has BEUDO, which is a similar emissions reduction ordinance that has been rolled out to commercial buildings but not yet to residential buildings, but will be in the near future. So people that are looking forward to that and want to get ahead of the process and prepare for electrifying their buildings they can get these high level decarbonization plans.
I also work in the LEAN Multifamily program, which does a lot of this implementation work and energy efficiency initiatives that have come out of the Mass Save efficiency programs. So I’ll go out to buildings and help scope new projects or install more energy efficiency equipment or electrified equipment for low income multifamily buildings.
00:04:01 Alina M
Nice. So you guys talked a little bit about decarbonization projects. Can you tell us a little bit about the four-step process of decarbonization?
00:04:09 Neil D
Yeah, we had a grant last year where we were really figuring out what decarbonization looks like. And so one of the things that has been evolving is this kind of four step process. We’ve got our first step of load reduction and indoor air quality.
00:04:29 Neil D
So when we think about the energy there’s the loads, and then there’s how we’re going to serve those loads. So the building needs to be heated. If you have better insulation, it’s be heated less, or cooled. And then we have how we’re going to serve those loads. So we’re going to start by trying to reduce the loads and having indoor air quality in our mind from the very start. There’s a lot of buildings that we see that do not have good ventilation systems currently, so if we were going to insulate and air seal those buildings, those indoor air quality issues would become even large health risks and issues for people.
00:05:06 Alina M
Mm-hmm.
00:05:11 Neil D
So that’s the first step, second step is going to be the optimization of the existing systems while they’re still there. We understand that not all owners are going to be able to put down the money to implement this entire decarbonization project that we would lay out all in one clean suite. And so we’re looking at, for some of these buildings, the zero over time approach.
00:05:31 Neil D
We’re looking between now and 2050, kind of a staged approach to get them to zero carbon overtime. And so when we say optimization of the existing systems, it’s if you have an existing gas boiler or domestic hot water system or ventilation system, we’re going to say “how can we work with that existing system right now so that we can operate that more efficiently while it’s still in your building?”
00:05:54 Neil D
Step Three is going to be electrification of all your systems that are currently using fossil fuels, and then Step 4 is going to be renewables. So we’re going to shift everything over to electricity and then try to serve all of those electricity needs with renewables as well.
00:06:12 Alina M
Mm-hmm.
00:06:14 Neil D
So that’s kind of our four-step process.
00:06:15 Alina M
Cool. So you guys recently presented at the NESEA conference. First can you say what NESEA is then can you also tell us what your research was about?
00:06:24 Neil D
Yes, so NESEA is the Northeast Sustainable Energy Association and this has been a great group because it really helps promote open and honest sharing between high performance building professionals and energy efficiency professionals, owners, property managers, utility program administrators.
00:06:45 Neil D
And I love the NESEA Building Energy Boston Conference, it happens every year in Boston, and it’s been such a great way to share what we’re learning and you can get so much out of the questions that we’re receiving from our presentations and meeting folks who are thinking about these things in similar or different ways. It’s a great spot to share ideas. And so our presentation this year was Equitable Data-Driven Domestic Hot Water Decarbonization.
00:07:16 Neil D
And so one of the things basically we didn’t mention in in what we do in New Ecology is trying to think about domestic hot water systems a lot. And at New Ecology we’ve always tried to take a very data-driven approach to our work and to be able to back up the recommendations that we’re making and the decisions that we’re making. So what we’ve been doing with this domestic hot water research is we go in and we directly monitor how much domestic hot water the building is using and we monitor the energy that’s being used to serve that domestic hot water load.
00:07:55 Neil D
We find that especially in a lot of the affordable buildings that we’re in, those buildings often don’t have really well sized systems. And so we can go in, we can directly monitor those systems and understand what those loads really are. The equitable part is bringing more information into the process so that that path to electrifying the domestic water system can be a lot more cost competitive and more projects can be approved through utility programs. When the costs can come down, those projects can screen better and we can provide some real savings, maybe those upfront existing costs.
00:08:37 Charlie S
With the flow metering work that we do, essentially the way that it works is we go in and we install these ultrasonic flow meters and they just attach on the outside of these domestic hot water pipes in the mechanical rooms of these buildings.
00:08:53 Charlie S
And from there we can measure the amount of water that’s moving out to the buildings and we can also see what temperature it’s moving out to those buildings. So from that we can understand the exact loads and the exact amount of hot water and the amount of energy that we need to heat that hot water in order to meet the loads of the building. And that’s why, if we have a really good understanding of exactly what a building’s using, then we can go forward and design a system that’s matching up with that super well.
00:09:27 Charlie S
If a building has a lower usage profile, it doesn’t need as big of a heat pump system or as much hot water storage in order to electrify that. Traditionally what happens is there’s a lot of these standard profiles that people will apply to buildings when they’re sizing these systems. If those standard profiles are used, they might not accurately match up with what the building really is using, and that’s where you get these discrepancies on the sizing of the system and oversizing of the system, which just ends up costing the building or the utility programs more money.
00:10:04 Charlie S
It’s really interesting when we look and understand the usage profiles of these buildings, because what you would expect to see is in the early morning hours, you’re not using much hot water at all—everyone’s sleeping. As everyone wakes up, you start to kind of see this spike of hot water usage around 6:00 AM and at peaks, maybe around 8:00 or 9:00 AM. And then it dips off a little bit towards the middle of the day.
00:10:30 Charlie S
And then as everyone comes home, starts cooking, taking showers, or whatever else, you get another peak of that hot water usage in the evening. So you kind of have this bimodal peak of hot water usage throughout the day. And then again, you know, after people start going to bed, it dips in the evening. You kind of expect in those early morning hours you would see hot water usage reach zero, but of course there’s humans in these buildings snd we see a whole host of different weird usage profiles. Sometimes it seems like there’s somebody who just left the shower on one night or, you know, maybe came home too late and just forgot to turn off the faucet. Or, you know, we’ve heard of people who leave their tubs running because they like the sound of running water at night. And so you see all these different extremes that we can pull out of this data and fine tune and do some you know very specific measures for a specific building that you might not understand if you didn’t do this measurement.
00:11:34 Charlie S
With that, you can ultimately design these systems better, but also design the fixtures—lower the water usage that the building’s actually using so that the system itself can not be as large.
00:11:49 Alina M
That’s great. Thank you guys for that overview. What do you mean by loads, Neil, you mentioned loads, what is a load?
00:11:57 Neil D
Yeah, so there’s loads and losses. And so the losses are the steps along the way where we lose energy or we lose water and we can try to reduce those and we can also try to reduce loads like Charlie was saying with lower flow water fixtures or something like that.
00:12:14 Neil D
But in the end, people are going to use a certain amount of domestic hot water at a certain kind of temperature and that’s the load. We are trying to serve that load.
00:12:24 Neil D
And so we have the thermal input to the system—the energy that we’re adding in. And then we have production losses, storage losses, distribution losses. And then finally at the very end of the line we get the energy in the water that’s going to the domestic hot water load.
00:12:43 Alina M
So when you talk about reducing loads, you’re not talking about trying to get people to shower less, for example. Like on your way in, Charlie, you mentioned there was a billboard that said, “tell your friend to shower tomorrow instead of today.”
00:12:57 Alina M
Your loads and the losses are really the systematic losses, energy escaping the system.
00:13:05 Neil D
Yeah. As we move through time, we keep finding other things that we currently think of as part of the load and we’re like, hey, wait a second, we can make some progress on that and we kind of relabel a piece of that load as a new loss that we can eliminate.
00:13:21 Alina M
Like what?
00:13:22 Neil D
Yeah. So I think about at my house the hot water pipes going to the shower are still larger than they need to be. So that means there’s just more water in those pipes and there’s a lot larger amount of metal there even. So when you turn the hot water on, you have to essentially purge all that cold water from the line. And then you have to heat up all that metal of the piping. And so in some ways, if you’re not going to be able to change those pieces of the system, that’s kind of part of your load in the building.
00:13:55 Neil D
But in new construction, when you can actually address those things you can have shorter pipe runs, more efficient architectural layouts, you can implement smaller pipe sizes. There’s been progress made on each of those recently.
00:14:11 Neil D
We are able to split out what we used to call the load and become more efficient at each of those steps in the process.
00:14:20 Charlie S
Just going back to the billboard that says to tell your friend to shower less or shower tomorrow—It’s a good idea of, you know, thinking about behavioral changes and getting people to understand their water usage or their energy usage. But when we go into these buildings and measure what’s actually occurring, often times we find these very large inefficiencies in the system. Whether it’s a leak that’s occurring on this hot water system where the building is using a gallon a minute of hot water every second of the day.
00:14:58 Charlie S
If you eliminate stuff like that, then, you know, it makes that one ten-minute shower that somebody took where they used 15 gallons of hot water or something like that, it makes that become a very small piece of it, where there are already these huge inefficiencies that we could directly address and people don’t actually have to change any of their behavior. And that’s a much harder problem to change. You could just switch out an aerator on a faucet, or switch a shower head, or stop the leak in your hot water system, that’s a much easier thing to address, and often has a much bigger impact.
00:15:37 Michelle M
How would you know an example like that if it was a leak or just like you said earlier, maybe somebody showering between 2:00 and 4:00 in the morning or leaving their tub on. How would you determine that in your process?
00:15:49 Charlie S
When we analyze all of our flow metering data that we get out of these buildings, we record the data essentially every 10 seconds. So we can see very high resolution data on exactly what’s being used every 10 seconds, every day of our recording period. And we like to record for a minimum of two weeks, but we’ve recorded much longer than that as well.
If you can see that a building is never reaching, you know, zero flow for every 10 seconds of that two week period, then you’re certain there’s a leak in the building because that’s just not normal. You would expect buildings to get down to zero flow for good portion of that 2:00 to 4:00 AM period. And if that isn’t happening consistently, you can definitely say there’s issues to be addressed.
00:16:43 Alina M
I don’t want to get too off topic, but I think there’s something in what you said earlier about paying attention to our energy usage as individuals while also focusing on the inefficiency of the system. And I think there’s something there for me and that the focus on environmental solutions, especially in the last like 20 years, was very focused on individual efforts rather than systematic changes. And so I think the work that you guys are doing is really interesting because it focuses on that system itself.
00:17:18 Alina M
The systems themselves could be more efficient, and while individual efforts are good, there’s also larger things in a multifamily building that can be done and have a big impact. It’s cool.
00:17:30 Neil D
Yeah, I think that when we start talking to an owner or tenants about what we’re trying to do with their domestic hot water system, we just want to provide a complaint free service. You can do whatever it is that you do, and we’re just going to try to provide that in the same or better way that you have been experiencing it. And we’re just going to do that more efficiently. You don’t get anyone who’s going to say no to that.
I remember I was at a presentation in a hot water forum. And this is where all the hot water nerds go to.
00:18:07 Alina M
Hot water nerds! All right, cool.
00:18:07 Neil D
Oh yeah, it’s I, I love it.
00:18:10 Alina M
It’s a world that I didn’t know existed.
00:18:12 Neil D
Totally. It’s eye opening. And there was one guy who said,” well, I think we should be using half gallon per minute misting shower heads.” And to get booed at the hot water nerds forum is like, you got people who really believe in this stuff, and being like, “no, nobody’s going to do that. We don’t even want to do that.”
00:18:37 Neil D
So yeah, there’s definitely progress to be made on people’s behavior and the water using fixtures that they have, but you can get pretty universal by it when you say “we want to do this in a way that’s going to cost you less, it’s going to be more comfortable.” It’s good all around.
00:18:56 Charlie S
Yeah and often times when we go into these affordable housing buildings, they’re domestic hot water systems are not working properly. So we’re actually going into buildings that have complaints of not having enough hot water.
00:19:12 Alina M
Like too cold or hot.
00:19:12 Charlie S
Too cold or, you know, they have to wait too long for the water to get hot.
00:19:18 Charlie S
What often happens in buildings like that where the owners are getting all of these complaints is the building maintenance will just go in and turn up all the settings on the boilers. So they say if we turn up all the temperatures, that will hopefully fix this issue, and Neil and I were just in a building last week where the recirculation loop, so this is the loop in the building that runs hot water around the building so that in a larger building when you turn on your fixture it’s not going to take a really long time for it to warm up because there’s already hot water nearby in the building. So that loop needs to be piped back into the hot water system in order to keep it hot. So as water goes around the building, it cools down and then needs to, you know, have a little bit more hot water added to it to kind of make-up that little bit of heat loss.
00:20:14 Charlie S
And this loop in that building was just piped back into itself, so it never had that make up hot water that kept the loop hot. And we looked at the settings on those tanks, on the hot water tanks and they were maxed out, you know, so those tanks are super hot, way hotter than they need to.
00:20:37 Charlie S
And then this also is a safety hazard for these people as well, because now when hot water does come into that system, it’s coming in at a temperature that’s way above the 130 degree maximum temperature that’s supposed to be allowed by code.
00:20:57 Alina M
Like scalding hot.
00:20:57 Charlie S
Yeah, so now for a unit in that building that might be pretty close to those hot water heaters, they could be getting 150° water out of their faucet, which could burn them very quickly. And by going into this building and seeing stuff like that, we can first make some basic recommendations just looking at the piping, but then use the flow metering to better size a new replacement system and help fix some of those underlying issues in a lot of these affordable buildings where it kind of gets left by the wayside.
00:21:30 Alina M
Yeah, that’s a great example.
00:21:32 Neil D
Yeah, it’s a really super example. We walk into the mechanical room, we say this one is going to have hot water complaints and then it’s also going to be potentially unsafe to tenants. And also the temperatures are all turned way up, so it’s not running efficiently either. You’re doing a bad job and paying more to do the bad job.
00:21:51 Michelle M
And you could install 1000 half gallon per minute misting shower heads in that building and it wouldn’t fix that problem.
00:22:00 Neil D
you would have a new problem with everyone moving out of your buildings.
00:22:02 Alina M
And getting burned by hot mist. Oh my gosh, that’s crazy.
00:22:08 Alina M
So if we talk about your research and the work you do in the buildings, what where the goals of the research that you do. So obviously like going into that building and looking at the piping, you know the goal of that is improving the experience of the residents in that building and saving the owner money. But you’re also monitoring systems and using that data. So tell us a little bit more about what you’re trying to get out of the monitoring aspect.
00:22:36 Neil D
I would say in our research we’re thinking about two pieces. We’re thinking about the loads to size systems and then the implications of properly sizing these systems. The implications are you have first cost implications, you have operational cost implications. In our research monitoring we are taking a look at total system efficiency.
00:23:02 Neil D
With that, in my mind, I draw a dotted line around the systems in these buildings. Then you have certain arrows going out-of-the-box and certain arrows coming into the box. The arrows going out— that’s when you turn on your shower head. When you have hot water flowing out, you have water flowing out of the system and energy flowing out of the system.
00:23:24 Neil D
And so then we have to have a water arrow entering into system and an energy arrow going in. And so we try to look at a building and say, great, we need to measure all of the arrows going out and all of the arrows going in. And so when we measure all the water arrows, we can say here is the ideal amount of energy that it would take to take the volume of water that this building uses and bring it from, say 50° to 120°. So that’s our ideal amount of energy.
00:23:59 Neil D
And then we also monitored all of those energy arrows going into our diagram. And so now we can say, here’s the ideal amount energy it would take, and here’s how much energy we actually used to serve that load. And that gets us a total system efficiency. And that that’s been a pretty unique thing that we’re able to bring to the table. So we’ve been refining this process over the last few years and it’s really interesting when you show these total system efficiency graphs, especially for gas fired systems, because we are seeing that if a system is way oversized, we do not get to operate that system at it’s peak efficiency.
00:24:44 Neil D
That has really proven the case that like, great, if you can properly size the system for the central gas fired systems, you might be able to get around a total system efficiency of 60 to 65% on average. But if you are oversizing you can be stuck with less than half of that efficiency.
00:25:06 Alina M
Can you talk a little bit about the sizing, like what does a properly sized system look like and what does an improperly sized system look like?
00:25:13 Charlie S
A good analogy to think about why sizing affects efficiency is to think about driving a car versus, you know, sitting in a parking lot, idling your car. The hot water system is, you know, the boilers and the tanks or the heat pumps and the tanks and the tanks always need to stay hot, so that when somebody calls for hot water, they have it there ready, so the system is always idling like your car would be and you never really shut it off because at any point in time somebody could want to take shower or turn on their hot water faucet.
00:25:49 Charlie S
And so when people start to use that hot water, then the system’s actually being useful, so hot water is coming out and it’s adding to that useful load of water moving into fixtures.
00:26:05 Charlie S
And so then you’re driving your car down the road, and that’s when if you’re sitting in your car idling, you get zero miles to the gallon. And if you’re driving down the highway, you get 30-40 miles per gallon, depending on your car. And so if we’re using that car, that hot water system to its capacity, running it and having hot water being used out of it, then that’s when we start to reach those peak efficiencies that we can see on the system. If we have a system that is way oversized, you know, too many storage tanks in the basement or too large of a of a boiler that needs to turn on and off all the time, then what ends up happening is that system is meant to serve a really, really high load in a building. It’s meant to drive 80 miles an hour down the highway or something like that. It’s got a bigger engine in it.
00:27:02 Charlie S
And if it’s only ever serving half of that, say, driving at 40 miles an hour down the highway, but it’s meant to drive 80, then you don’t reach its peak efficiency. You’re either idling a lot of the time or not using a lot of the hot water, but you still have the heat losses out of the tanks. The heat losses out of the boiler when it turns on and off.
00:27:26 Charlie
But the load in the building never changes. It changes throughout the day, but the profile of its usage is pretty consistent. So if you match up that system, you know size the storage tanks down and decrease the size of the storage tanks to meet however much water needs to be used in that building, then as those two pieces of the puzzle meet up—the load in the building and the size of the hot water system—then you can say, “OK, we’re utilizing our system to its maximum.” And when we’re utilizing it to its maximum, that’s when we are driving it down the highway for the vast majority of the time as opposed to idling, then we see those higher efficiencies in the system.
00:28:17 Michelle M
So what you’re talking about with the oversizing is like having a racing car and using it to go get groceries or something. It just doesn’t make sense. But is there ever any situation where it’s undersized? Like, what if you had a bicycle?
00:28:30 Neil D
Yeah, there’s, you know, a lot of different ways that you can fail to serve the load of the building and we see that in our data sometimes as well where there’s more hot water being used in the building than the system can keep up with. And so that kind of brings us to the thought of like our system traditionally sized, and then how are we proposing that you do it.
00:28:54 Neil D
There have been a lot of buildings that don’t have any data when they go into sizing the system, and so you’re sizing the system based off of assumptions. You’re assuming how many people are in the building, how much water all those people are going to be using and when they’re going to be using it. You’re coming up with this assumed load and profile. And then you can choose how you want to serve that load. You can have a really big boiler and a very small amount of storage. We call that the recharge rate. They have a high recharge rate, but a low storage volume.
00:29:27 Neil D
If the building’s using 100 gallons of water per minute, you can just light a really big fire in your boiler and create that water just as quickly as it’s being used. The other end of the spectrum is you can have a larger storage volume and a smaller water heater. Now when you’re using 100 gallons per minute or something, you know that that’s not going to last a very long time and we’ve got some storage and we’re just going to be able to pull that demand off of the storage and serve that load. We’re going to recharge the storage tanks over a longer period of time with a smaller water heater. So those are kind of the two extremes of the spectrum and you can be anywhere, you can really be on any part of that spectrum. When we get into heat pump systems, the heat pumps themselves are more expensive per unit of heat output. It would cost you a lot more upfront to buy like an instantaneous heat pump, water heater. So for central heat pumps, we’re shifting a lot more towards the storage end of that spectrum.
00:30:37 Neil D
So we’re going to have a lower recharge capacity and more storage volume.
00:30:43 Michelle M
Heat pumps—you said they were higher upfront costs or higher in general to run?
00:30:48 Neil D
There are a higher cost if you need a water heater that can output 100 units of heat per hour. You can have a boiler that outputs 100 units of heat per hour that’s going to be a significantly lower cost than a heat pump that can output that same amount of heat per hour. For the same size, the heat pumps are going to be more expensive.
00:31:11 Alina M
So we recommend heat pumps a lot at New Ecology, so what’s the benefit of them?
00:31:15 Neil D
Yeah, totally. So the benefit is that A. You’re moving towards electrification and so when we talk about electrification, it’s part of an overall path to decarbonization, because we’re going to switch you from burning fossil fuels at your site, we’re going to switch you over to electricity, and then we like the term riding the Green Wave of the electric grid that where the utility companies have a lot of plans to be providing electricity in lower carbon ways and more sustainable energy.
00:31:49 Alina M
But what if someone doesn’t care about their carbon? Would they still want a heat pump?
00:31:53 Neil D
Yeah, so they operate at much higher efficiencies. For the gas firing systems, you’re not getting efficiency higher than 95% is like a rated efficiency and then you switch over to heat pumps and
you’re looking at annual efficiencies like 200%.
00:32:13 Alina M
Oh, interesting.
00:32:15 Neil D
Those are making sense here in Massachusetts, where we have high electricity prices.
00:32:22 Alina M
I did learn in the last episode that energy is a lot less expensive in the Mid Atlantic, and that makes a lot of things make a lot more sense.
00:32:30 Alina M
I have sort of like a philosophical question where we were talking about sizing. Have you ever gone into a building and it was sized for different cultural or familial expectations than we have now? For example, if you had a building that’s like two-bedroom, three-bedroom apartments, but they’re all occupied by single people, or single studio apartments occupied by two people and a kid, your hot water usage is really different. And I imagine some of the hot water systems were sized decades ago. So are you seeing anything in terms of shifts in building usage and housing trends that affects the hot water needs of a building?
00:33:20 Charlie S
If there’s a substantial rehab of a building where there’s a lot of work being done, then the system might be resized with, you know, the traditional profiles and then they’ll, you know, say, OK, the category of people living here fall into this usage profile, high usage, medium or low, and then they’ll base the size of the system off of what those people would typically use, but unless it’s a significant project for the building where they’re doing a lot of different types of work and the hot water is one part of that you probably won’t see the full resizing of the system in that work being done, but as these regulations are being pushed and people are moving towards electrification, it becomes really important, especially for these affordable housing buildings, to make sure that they are sizing their systems properly because it does have a really significant upfront cost impact and also potentially operating cost impact.
00:34:26 Neil D
When a system is being sized, most engineers will reference ASHRAE in some way. So ASHRAE is the American Society of Heating, Refrigerating and Air Conditioning Engineers, and they’ve got guidelines for everything. Everything.
00:34:47 Alina M
Guidelines for everything! These are your hot water nerds?
00:34:49 Neil D
This is like the organization that, like, lays out guidelines for sizing everything, how much air flow you need in the apartment, what size pipes you need… guidelines for everything building.
00:35:01 Neil D
They also have guidelines on how many occupants will be living in different units of different size. That kind of assumption of like occupants per apartment. And then they have these ASHRAE low, medium and high usage profiles, gallons of domestic hot water used per occupant to sort your population into a low, medium or high profile.
00:35:31 Neil D
So you’ve got those two assumptions of number of people per unit and then water usage per occupant. That data is really old as well.
00:35:42 Alina M
Oh interesting.
00:35:44 Charlie S
When I was at the hot water forum two years ago, I actually I was talking with one of the guys who was on the team that built those usage profiles and I mentioned to him obviously the work that we’ve done here measuring all of these different loads and he talked me through what their approach was for creating these usage profiles and essentially what they did is went out sampled a bunch of different buildings and different types of populations and created these usage profiles based on that data that they collected. But it was 40 years ago that they did that and collected all of this data and created these usage profiles.
00:36:33 Charlie S
And he mentioned to me he’s like, this was good work that we did back then and it made a lot of sense with all of our existing knowledge. But a lot has changed since then and you know, that’s why all these people come together and talk about how this stuff is changing so that we can hopefully update stuff like that, because not every building is going to be able to have the service of somebody going in there and measuring their real loads. But if we get enough buildings that do that, then we can use that data to then inform potentially new usage profiles or you know something that’s coming down the line to update those guidelines. Things have changed. People have changed. The people that live in these buildings are very different from the people that lived in them 40 years ago. And also 40 years ago, there weren’t low flow aerators in buildings, so that has a significant change. The actual system has changed and its loads have decreased. And taking stuff like that into account, making sure that these buildings are updated with the newest equipment and seeing how that affects its actual usage and then measuring it and hopefully informing new guidelines.
00:37:51 Molly Craft
I’m Molly with your Mass Save minute. Today, we’re diving into options for domestic hot water upgrades offered by Mass Save. Mass Save provides a range of incentives to help homeowners improve the efficiency of their domestic hot water systems. Upgrading your water heating system not only saves money on utility bills, but also reduces energy consumption and environmental impact.
00:38:12 Molly Craft
One option is the High Efficiency Domestic Hot Water Initiative which offers rebates for upgrading to high efficiency water heaters. This includes heat pump water heaters, which use significantly less energy compared to traditional electric or gas water heaters.
00:38:25 Molly Craft
Another option is the Home Energy Assessment, which provides personalized recommendations for improving energy efficiency, including upgrades to your hot water system. This assessment helps homeowners understand their energy usage and identify cost effective upgrades. Additionally, mass save offers incentives and financing for installing low flow fixtures and water efficient appliances, further reducing water usage and associated energy costs.
00:38:49 Molly Craft
Whether you’re replacing an old energy intensive water heater or looking to optimize your hot water system, Mass Save’s incentives make it easier and more affordable to upgrade to energy efficient options. Head over to the Mass Save website at masssave.com M A S S S A V E .com to learn more. That wraps up today’s Mass Save minute.
00:39:09 Molly Craft
Thanks for tuning in. Remember upgrading your domestic hot water system isn’t just about saving money, it’s about conserving resources and reducing your environmental footprint. Until next time, stay informed and energy conscious.
00:39:24 Alina M
So, you talked a lot about how the system works, and I’m going to repeat back to you how I understand how the hot water system works and you can tell me if I’m understanding it. So you’ve got these inputs. The two main inputs are the water and the energy. and water plus energy makes hot water and then it flows out of whatever, the boiler, the storage, right, and then it’s losing it either through the storage itself, the pipes on the way to get there. Maybe just someone running the faucet when they don’t need it. What else am I missing about how this system works?
00:40:05 Neil D
Yes, that’s good. I think that’s the view of like the whole system when you have a box drawing of the whole thing, you’ve got those arrows in and arrows out.
And there’s a lot of different configurations of like what’s actually going on inside that box. And so there’s all different options when you talk about the fossil fuel equipment and also with electric systems.
00:40:29 Alina M
So that’d be like the energy arrow going in, could either be gas or electricity.
00:40:33 Neil D
Yeah. Yeah, right. So that energy in can be in whatever energy form.
00:40:39 Alina
And it’s preferable in most ways, I guess many ways for it to be electric, because then you can get the benefit of the grid itself becoming greener and becoming more renewable.
00:40:51 Neil D
Yeah, exactly.
00:40:52 Alina M
And that’s what you mean by riding Greening of the Grid Wave.
00:40:55 Neil D
Yeah. When I say that, we have a good example here in Boston. So BERDO has what they think the carbon intensity of the grid is going to be for each year between now and 2050. There’s more fossil fuels in that utility mix right now, so we have a higher amount of carbon per kWh right now. They’ve got that decreasing overtime as more renewables are included in that utility mix.
00:41:26 Alina M
And BERDO’s the regulations for Boston. So basically, they’ve done an analysis of what the carbon output will be based on their assumptions about what’s going to happen to the grid as a whole.
00:41:37 Neil D
Yeah, exactly.
00:41:39 Alina M
OK, I’m following you. Yeah, this is great.
00:41:41 Neil D
Yeah. So it’s like a carbon forecast of the utilities.
00:41:47 Alina M
Cool. OK, so that energy is going in. Maybe it’s a green grid, maybe it’s not. But there’s energy going in, and then there’s the water going in. And then within the box?
00:41:57 Neil D
Yeah. So within the box usually you have some sort of water heater. You have a storage tank and we’ll call that the primary storage. That’s usually kept at a higher temperature in that primary storage for safety reasons. You know to prevent things from, bacteria from growing in that tank.
00:42:22 Neil D
And then usually you’ll have a mixing valve then to mix down that higher temperature from the primary storage tank. You’ll mix that hot water with cold water that’s coming off the street, and so your mixing valve then will mix that to try to keep it consistent, you know, 125°, that’s the domestic water supply going out to the tenants.
00:42:45 Alina M
OK, because the water in the storage is hot enough to prevent bacterial growth. But that’s too hot. Scalding. So you can’t just have that come out to the faucet. It has to be mixed with colder water.
00:42:56 Neil D
Yeah. We talked about like 140° as storage temperature to kill off the Legionella bacteria.
00:43:04 Alina M
So scalding water mixing with street water, making faucet water.
00:43:11 Neil D
Yeah, all beautiful terms.
00:43:14 Alina M
Yeah, that’s that makes water so great. Yeah. OK.
00:43:19 Neil D
And so we have that domestic hot water supply coming out of the mixing valve going up through the distribution loop, so on the layout that’s like our supply and then we, as Charlie was talking about, bringing that water back and that’s going to be our recirculation.
00:43:36 Neil D
So we have 120° water or something going out as our supply and we’re bringing that back. We’re recirculating that so that we have hot water close to all the fixtures in your building.
00:43:49 Alina M
And that’s kind of the main difference between a multifamily and a single family, because you don’t need that for a single family home. You wouldn’t have it circulating throughout the building. You’d have just a storage tank that’s close enough to all the fixtures that you wouldn’t really need that loop? Seems like the Loop is the complicating factor with multifamily.
00:44:06 Neil D
There are different technologies for single family. Yeah, mostly we’re seeing recirculation distance in the larger buildings and so then that recirculation water comes back to the mechanical room, it’s a big loop up through the building, so there’s heat loss from that. If that’s coming back and has lost 5-10° or something, then we’ll need to heat that back up a little bit, so there’s different ways that that can be done.
00:44:36 Alina M
OK. I get it!
That reminds me of something you mentioned in the NESEA presentation. You said that 25% of the building’s energy usage comes from its domestic hot water system.
00:44:51 Neil D
Yeah, something around there.
00:44:53 Alina M
To be specific, you said it’s a juicy piece of the decarbonization possibilities in the building, which I thought was a really Primo quotation that we should probably insert here.
00:45:04 Neil D (Recording from NESEA presentation)
Zooming into domestic hot water today. Domestic hot water makes up an average 25% of multifamily energy end use, so that’s a pretty juicy piece that we can go after.
00:45:18 Neil D
Yeah, it’s a large enough chunk that it’s worth spending some time on to figure out how we can do it right.
And it can be an easy chunk to go after. It can be a lot easier than dealing with a whole building envelope.
00:45:36 Alina M
Yeah, right.
So what are some of the reasons why a building owner or the operator of a building might want to look at their domestic hot water system?
00:45:48 Neil D
The main points here are we’ve got the potential for cost savings by going to a more efficient system. There’s a lot of different incentives available right now. Incentives for efficiency upgrades of any kind. Or there are incentives that also have decarbonization goals attached to them. So you have to be electrified or using heat pumps to get those incentives.
00:46:14 Neil D
You know those incentives are driving a lot of the conversation for people looking to replace their systems. Also there are more fines or penalties coming about now. So with BERDO there will be compliance payments I think they’re called, if you’re not meeting the carbon goals for your building type. There’s also the electrification aspect is a driver for these people as well.
00:46:45 Michelle M
Correct me if I’m wrong, it sounds like compared to what we talked about last episode with Marty and Pat, right, we talked about general decarbonization, and how often it’s a zero over time process because it takes so long, there’s a lot of upfront cost with not a lot of upfront savings. But it sounds like a properly sized domestic hot water system, some of that cost savings that you see might actually be quite upfront.
00:47:06 Neil D
There’s like 3 categories that we think about. There’s like the cost savings, which I guess gets split out into like first costs and operational costs. And then we look at carbon savings, and we look at energy savings. So we ran an analysis of about 10 buildings last year and what we were finding was that, for these buildings, you know around the Boston area, making this switch to a central heat pump water heater system was going to be a slight increase in their utility costs to operate the domestic hot Water system. It was going to be an energy savings. It was going to be a carbon savings. So I think it’s important to be clear about that in these examples, we were seeing a cost increase. It depends on your gas rate and electric rate where you are.
00:47:59 Charlie S
One thing to add on to that is that when we’re thinking about these cost savings we have to think about kind of what we’re comparing it to. In this case, the upfront cost of these systems might actually be more along with, you know, operational costs. It’s comparing it to these older gas fired systems that traditionally are simpler pieces of equipment with lower upfront costs. And then gas, which traditionally is a very cheap form of fuel. But as these regulations come into place and people think more about the cost of carbon and that gets tied into cost of gas, the price of gas is likely to increase in the future as more people electrify and move away from it as a traditional fuel source. Instead, take comparison of OK what’s our cost savings of electrifying this domestic hot water system versus what’s the cost of electrifying it with a properly sized system, that has been, you know, based on these measurements. If we’re electrifying the system, no matter what and that’s our baseline, then doing it in this way where we measure those upfront loads, we can really decrease those upfront costs by you know 20% I think we’ve been seeing in some of these buildings compared to those traditional ASHRAE profiles. that in turn is going to help you save on your operational costs as well, because your system won’t be oversized.
00:49:35 Alina M
Can you say that again you decreased what by 20%? That’s a lot.
00:49:39 Neil D
From the load testing, we use this information to go ahead and size central heat pump water heater systems ourselves. We have a lot of information from our experience actually installing these systems, what a system of this kind of size is going to cost people. And so we really have a comparison of like if this system was sized, using traditional sizing methods versus the actual measured data, we are seeing a cost reduction of about 20% in that system first cost.
00:50:12 Neil D
When you directly monitor and you have the real data, you feel more comfortable with the data because we can see how frequently these different loads are happening.
00:50:22 Charlie S
Ultimately, they don’t have a good solid baseline for what they’re basing their system sizing off of. When we go in and measure exactly what they’re using, they’re going to feel a lot more comfortable using your usage profile that we’ve measured in this building to size their systems.
Then you can be very confident in your system sizing. And that’s, you know, that’s where we’re seeing these cost implications of first moving from the assumptions of the profile to the actual profile is that 20%.
00:51:02 Alina M
So that’s really the crux of the research is that if you can monitor it, you can make it more efficient than what was originally designed, and you can also check for inefficiencies in the system that were not intended like the set points being too high. So the main piece for an operator is that there’s a benefit to monitoring.
00:51:24 Neil D
It yeah, it allows you to get a system that is going to serve your load successfully and do so in a way that is most cost, carbon, energy efficient. And we’re also going to minimize your upfront cost to get that system that does that.
00:51:43 Alina M
That’s Cool.
00:51:45 Neil D
Yeah, it is. You know, it’s important to frame this within our larger decarbonization projects that we’re pitching as well, because for all of those projects, we’re able to provide a path that is not going to be increasing the annual utility spend.
00:52:06 Michelle M
And that can benefit the owners and managers or the tenants, depending on how things are laid out, correct?
00:52:12 Neil D
It’s an important piece to be able to tell them by saying that we’re going to electrify everything they’re like, hey, hey what’s that going to do to my monthly bills?
00:52:19 Neil D
And so it is very relieving to be able to tell them they’re not going to go up based on like using today’s rates.
00:52:28 Alina M
So it’s a win win. One is decarbonization and one is cost.
That’s great. So what should someone do if they want to find out more about decarbonization?
00:52:41 Neil D
Right now we have some grant funding that’s available specifically to help nonprofit owners be able to bring this domestic hot water metering into their projects, you know, as part of a larger scope to take a look at the whole building either through a short term like deep energy retrofit, doing a lot of work all at once, or if it’s gonna be a zero overtime approach, we’re gonna go through multiple phases of upgrades, a planned process.
00:53:17 Alina M
That’s great. How does a resident experience the impacts of our work in the building?
00:53:23 Neil D
They should not experience any difference. That’s the number one thing with what we’re doing here is we just want to provide consistent, reliable, fast response to people using hot water. We don’t want them to have to think about it.
00:53:41 Alina M
Well, I want to thank you guys for coming and talking about the domestic hot water.
I learned a lot. Hopefully I understood everything, I think I did though.
00:53:51 Michelle M
Yeah, I think I I’m getting there.
00:53:53 Alina M
So thanks so much. We really appreciate your time. We hope to have you guys on again.
I’m sure you’ll do some more interesting work in buildings and research so hopefully have you future season as well.
00:54:08 Neil D
Yeah, thanks for having us. It’s fun to talk through this stuff together and it’s always good to break it out to other groups.
00:54:16 Alina M
Thank you guys.
00:54:17 Charlie S
Yeah. Thanks. Yeah. Thanks for putting this all together.
00:54:20 Alina M
Thank you to Neil and Charlie for that in-depth overview of domestic hot water efficiency. We encourage you to listen to our last episode with Marty Josten and Pat Coleman where we talked about decarbonization generally and about improving the efficiency of existing buildings. We gave an overview of a lot of these concepts and terms in that episode so it might be a good place to start if you’d like to explore more.
00:54:42 Alina M
Please like, subscribe and follow wherever you’re listening, and check out the transcript or the show notes on newecology.org/buildingwell/podcast. Thank you.
00:54:54 Michelle M
Thank you.
00:54:56 Molly C
This episode was made possible by the Mass Save Community Education grant.
00:55:01 Michelle M
The BuildingWell season one podcast committee at New Ecology is led and organized by Alina Michelewicz and Michelle Moran. Mass Save minutes by Molly Craft. Production, editing, and music by Michelle Moran. Video editing by Michael Abdelmessih. Episode notes and description by Neil Donnelly. Transcript by Michelle Margolies.