The future of home heating: Hybrid home heating systems offer energy savings and reduce GHG emissions

By Leila Lemghalef with Jeremy Sager, CanmetENERGY-Ottawa

In the hot summer months, optimizing your home heating system is probably the last thing on your mind. But they’re the perfect time to think about it. And they’re also the perfect time for Natural Resources Canada (NRCan) researchers to crunch the numbers, especially after spending a cold winter measuring energy use and comfort levels in a series of test homes using hybrid heating — the combination of a natural gas furnace with an electric air source heat pump.

It was cold but it was time well spent, since researchers from CanmetENERGY–Ottawa have identified hybrid heating as one way to save energy, reduce greenhouse gas (GHG) emissions and build Canada’s resilience to a changing climate and changing energy prices.

NRCan researchers measured a 30 percent drop in GHG emissions in one complete heating season.

NRCan research engineer Jeremy Sager and student Alexandre Bouchard visits a test house near Ottawa.

“Our role is recognizing the potential, recognizing the opportunity,” says research engineer Jeremy Sager, whose focus is on the residential sector. “We’ve done research on air source heat pumps for several years now, and we started thinking about the possibility of replacing an air conditioner with a heat pump. When a person’s aging air conditioner needs to be replaced, what if it was switched with a heat pump? That way, the heat pump could do some of the heating and save energy.”

Make the switch to save energy

So they set out to find answers. And this past spring Jemery and his colleagues finished monitoring three model homes equipped with hybrid heating systems in a new housing development east of Ottawa. Their early findings show that energy savings are substantial. Over the complete heating season, they tracked a 30 percent reduction of GHG emissions for the hybrid system with smart switching controls versus the natural gas furnace alone.

 “During one particularly cold day, there were 7.58 kilograms of CO2 emissions reduced while the heat pump ran from 12 a.m. to 6 p.m.,” says Jeremy.

Space heating: the biggest energy end-use in Canada

These energy savings are especially significant when you consider that space heating accounts for more than 60 percent of the energy consumption in the average Canadian home. What’s more, space heating is the single biggest energy end-use in Canada and the country’s second-largest contributor to GHG emissions.

Hybrid heating reduces energy consumption and GHG emissions by relying on the heat pump at moderate outdoor temperatures and during off-peak times, when it is cheaper to heat with the heat pump. Then the system switches to a natural gas furnace in cold temperatures and at peak times.

See how Jeremy and his team measure energy savings and comfort levels in a test
house equipped with a hybrid heating system in this YouTube video

Transcript

Jeremy Sager:

I’m Jeremy Sager. I’m a research engineer at CanmetENERGY Ottawa in Bells Corners. And my role is to assess the performance of different, more energy-efficient heating ventilation and air conditioning systems. Today, we’re checking data together with Alexandre, our CO-OP student. We’re checking the data from the systems, making sure everything’s working as expected.

Alex is checking — for example, right now, he can log into these sensors, and then he can see the data from the sensors on his phone.

Alexandre:

So the loggers collect data every five minutes, and the last time I came to collect data was three weeks ago. So do the math: five minutes for three weeks — that’s a lot of data. So it takes a couple of minutes for my phone to collect everything. And then it generates a mini-graph, which we can see right here. And then I export that to Excel, and I send that to the office, and we can analyze that at the office.

Jeremy:

We’ve done research on air-source heat pumps for several years now, and so we’ve started thinking: Well, what about the possibility of replacing an air conditioner with a heat pump so when your air conditioner gets old, the heat pump can do some of the heating and save energy. So that’s what we did in this house.

And then we started to look at the energy consumption and comfort impact. So this is one type of air source heat pump for a hybrid system outdoor unit. It’s side-discharge, so it draws air in from the side and blows air out the front. So if it’s snowing or there’s freezing rain, that’s going to land on top of the unit and not impact the air flow of the unit. Once it gets above minus eight outside, and if it’s off-peak, then it’s going to switch to the heat pump.

There’s also a phone app for this. And the phone app tells you what the system has been doing over the last 24 hours, what it’s going to do over the next 24 hours, how much energy savings there were and whether there was greenhouse gas reductions. This is the system on February 8, and we can see that the greenhouse gas emissions reductions were 30 percent for that day and there was eight kilograms — well, 7.58 kilograms — of CO2 reduced, and it ran the heat pump from 12 am to 6 am.

We’re expecting greenhouse gas emissions reductions of 20 percent or better, and that really depends on location and what you set your thermostat to. But that’s ballpark what we expect from this approach.

Turning smart controls into smart energy savings

This is all done by using Wi-Fi–enabled smart switching controls that automatically send a signal to the system to switch to the furnace or the heat pump, depending on the least expensive mode of operation at the time. The smart system takes into account various factors: natural gas and electricity prices, time of use, outdoor air temperatures, performance of the natural gas furnace and performance of the heat pump.

Electric air source heat pumps are designed to provide efficient space cooling as well as space heating. They can be retrofit and work with any fossil fuel furnace or combination system powered by natural gas, propane or oil.

Environmental benefits and economic savings

In Canada, 35 percent or 5.1 million homes are currently heated with natural gas furnaces in areas with low-cost natural gas and higher-cost electricity, such as Ontario. Hybrid systems present a cost-effective method of reducing GHG emissions in these homes.

NRCan’s contributions to the implementation of gas hybrid systems in Ontario and Canada were recently recognized by Better Builder magazine. The magazine pointed out that a carbon tax would not in itself be sufficient to change people’s reliance on natural gas furnaces as the primary source of heat

Learn more about energy-efficient homes in this Simply Science podcast

Transcript

Joël Houle (Host)

Welcome, everyone, to Ask NRCan! This is a podcast series where we sit down with our experts to talk about an aspect of the work that we do here at Natural Resources Canada.

Today, I’ll be talking to an engineer who works on projects and initiatives aimed at increasing energy efficiency in homes. For those of you who are new to the show, we call this series Ask NRCan because we want to hear from you. The purpose of the show is to share with you not only the type of science that we do but also why we do it.

So, at the end of the episode, if you have any questions on this topic, head to Twitter and tweet at us using the hashtag “#AskNRCAN”. Our experts will do their best to answer all relevant questions. Sounds good? Let’s do it!

My guest today is Chris McLellan, a senior technical advisor that works for the office of Energy Efficiency at NRCan. Chris, thank you for joining us.

Chris McLellan

Thank you, it’s a pleasure to be here.

Joël

Can you start by telling us a little bit about the type of work that you do?

Chris

Okay. Well I work at the office of Energy Efficiency in the housing division, and, really, our primary focus is on improving the energy efficiency of housing for Canadians. And that includes both new housing and existing housing. So you know, we’ve run programs in the past that had incentives for people to improve the energy performance of their house, and we also run voluntary programs for builders to build better performing houses for Canadians. So that’s really what we’re looking at.

Joël

So, NRCan is looking ahead in regards to how we can build more efficient homes in Canada. Can you expand a little bit on this topic?

Chris

Sure. Well, maybe we’ll look back a little bit in history; it’s just kind of interesting. You know, NRCan’s been doing energy efficiency for housing really since the early eighties. In 1982, NRCan launched the R2000 program. And I remember as a kid, sitting around the breakfast table with my father — who’s an engineer and pretty obsessive about energy performance — then talking about this program to me, and it’s kind of funny ending up here later.

But the R200 program came out of some work that was done in Saskatchewan in the seventies, and you might have heard of the passive house program. There’s quite a bit of talk about that right now, and, really, the passive house program is taking that old R200 in Saskatchewan conservation house work that was done here and kind of repackaging and shipping it back to us. But since then we’ve continued with the R2000 program, and that was really a program that led the way for innovators. It always had a targeted energy performance that was about 50 percent better than the typical house that was being built.

More recently, we’ve brought in the ENERGYSTAR for New Homes program, and that’s somewhere around 20 to 25 percent better than the typical house. So these are voluntary programs. And then in about 2009, there was support from the Canadian Homebuilders Association to put energy efficiency into the National Building Code of Canada.

So, then, in 2012, the energy performance requirements were published in the code. So we ended up with this nice, sort of, ecosystem where you had the R2000 program leading the way with innovators and groundbreaking work being done. And we had ENERGYSTAR for New Homes kind of picking up the mass market and getting those energy efficiency techniques and materials out there in the broader way. And then we had the code come in behind and kind of picking up those that needed a bit of help.

So, right now we’re looking at ramping up that energy performance in the code and starting to put different performance levels in the code. So, in a way, it’s replicating what has been done in the past with voluntary programs leading the way. But we’ll end up with sort of the higher-performance energy requirements right in the code itself. And that will give the provinces and territories who are ready to move industry to higher performing houses a tool to do so through regulation at the provincial or territorial level.

So, we see in B.C. right now, there’s a lot of work that’s been going on there. They have what they call their Energy Step Code, and that’s the same sort of idea. There’s different performance levels. I think there’s about five in there, and it basically starts off with the lowest performance tier. You just need to test the airtightness of your house, model it so that we know the energy performance through simulation. And then the tiers keep going up from like 10 percent better than to 25  percent, I think, 40 percent and then roughly around 70 to 75 percent better. So we’re going to see that sort of thing happening out probably in the National Building Code as well.

Joël

If I can ask you a more technical question: reading up on this online, it says that high-performance home help homeowners benefit from better indoor air quality and fewer mold issues. The way I understand it is that this might be hard to do because energy-efficient homes tend to be more sealed, so air tends to be more stale. So then you would need to bring more air in, which would seem to lessen the efficiency of the energy consumption. How does that work?

Chris

So, you’re right. We have been building homes tighter and tighter and the reason for this is two-fold. We found air tightness is the most cost-effective way to reduce your heating load in the house. And the trade-off, though, is that you need to bring in ventilation air to make up for that. You’re not getting that natural air leakage, so you have to run a device. And, typically, what we do or what we recommend to homeowners is to get a heat recovery ventilator — an HRV, or sometimes they’re called ERVs. So these basically are air-to-air heat exchangers. So you’re exhausting your stale air from the indoors, and you’re bringing in fresh air from the outdoors. And as those two streams pass by each other in this self-contained box, heat is just transferred between the outgoing air in the winter and the incoming air in the summer. So, you’re still getting that ventilation air that you need, but you’re not having a huge energy penalty, let’s say. We know it costs energy to heat that ventilation. But because you’re transferring the heat from the outgoing to the incoming, you’re saving energy in doing so.

Joël

Oh, it’s incredible the amount of technology we have today.

Chris

It’s interesting that technology came out of that project in Saskatchewan in the seventies, and it was basically brought into the mainstream in Canada through the R2000 program. And now we’re seeing that technology being used all over the world.

Joël

So with all this new technology and the new code requirements, how does that affect the price of those houses?

Chris

Well, we’ve seen from our energy efficiency programs in the past, that it does cost more to bring this technology into a new home. Part of what’s happening with the Code is that we’ll see better adoption of these sorts of technologies. As these are adopted more fully in the market, the costs do come down; we’ve seen that in our programs. So, if you look at buying a house, you got two things that you really need to worry about; you’ve got the cost of the house, and you’ve got your operating cost. And, in a certain way, the cost of the house is going to be, typically, people have a mortgage. So they know their cost for this house as a mortgage that they might be paying monthly and then their cost for their utilities.

So as you improve the energy performance of the house, your utility cost comes down. And hopefully you could find a nice balance between where maybe your mortgage has gone up a bit, but your utility cost had come down — but, on a monthly basis, you’re spending the same amount of money. Of course there are some things that you might not see the savings that you hope for. But when we do the work on the Code, we do quite a bit of analysis to make sure that the requirements that are going in there are good for Canadians.

Joël

So if we could take a step back, I’m kind of curious to see why the Government of Canada is focusing so much on more energy efficiency homes?

Chris

I think there’s two things we’re really looking at around climate change, and one aspect of that is mitigation, so we could think of energy efficiency as part of mitigating climate change. The other aspect of that would be adaptation to climate change, and that’s also very important when we’re talking about housing. So, that is adaptation to extreme weather events: we know that there’s more frequent power outages, stronger winds, sometimes heavier snow loads. Energy-efficient houses are quite good in both of these regards. Because the more insolation you have, the less heat you need in the house, and if there is a power outage or you’re losing access to your utilities, these houses stay warmer for a longer time. So in that way, it does bring some resiliency to the housing. But, really, this is all about reducing our impact on climate change. We see about 17 percent of emissions of greenhouse gas emissions or GHGs. Quite often they’re attributed to housing in Canada, and if we can reduce our energy consumption, we know we’ll also be reducing our GHGs.

Joël

Fair enough. What can Canadians do to learn more about either buying a new energy-efficient home or learning how they could make their current home more efficient?

Chris

A good place to start is coming to NRCan’s website at the Office of Energy Efficiency. I would highly recommend getting an energy advisor, whether you’re thinking of building a new home or hiring a builder to build you a new home, or you’re thinking of renovating a home. So we have a network of registered energy advisors. They’ll come into your house, or they’ll look at your proposed building plans. They can make recommendations on the characteristics of house that would affect energy performance and help you to build a more efficient home. Through that program — that’s the EnerGuide rating system, and I think it should be pretty easy to find information about that on our website.

Joël

Perfect. Thank you so much, Chris, for your time today.

Chris

Thank you, it’s been a pleasure.

Joël

So, this is the end of the episode, but, like always, it doesn’t mean that it’s the end of our conversation. If you have any follow-up questions for our experts, get on Twitter and tweet at us using the hashtag “#AskNRCan”.

Also, if you are interested in learning more about the scientific work that we do at Natural Resources Canada, check out our online magazine called Simply Science. We have a ton of great content for you, including articles, videos and previous episodes of this podcast.
If you check out the podcast page for this episode, we’ll have links available to any relevant material so you can learn more about what we talked about today.

The best way to find Simply Science is to either Google it or click on the banner from our website at nrcan.gc.ca.

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That’s all for us today. Thank you for listening! We look forward to hearing from you, and we’ll see you next time.

That’s where hybrid systems come in. Incorporating an electric air source heat pump to help reduce reliance on natural gas for space heating can make sense economically and environmentally. In Ontario, the operating cost of a hybrid system is similar to that of a natural gas furnace heating system. There are modest utility bill savings for moderate outdoor temperatures and off-peak time of use. Homeowners ready to replace an aging air conditioner can consider replacing it with an electric air source heat pump designed to provide efficient space cooling as well as space heating.

Hybrid systems are not new equipment, but they are still emerging on the market and becoming more widely available. To enhance market uptake, CanmetENERGY and NRCan’s Office of Energy Efficiency are collaborating with manufacturers of equipment, thermostats and controls to optimize the performance of hybrid heating systems. Some of the data and analysis the CanmetENERGY team collected at their test site this winter will be included in a report of use to utilities, manufacturers, designers, the housing industry and policy-makers.

CanmetENERGY–Ottawa leads the development of energy S&T solutions for the environmental and economic benefit of Canadians.