Electrification Myth-Busting: Heat Pumps Are Ready for Cold Climates Today

Bring up the topic of heat pumps and inevitably the question
comes: But do they work in the cold? A perception persists that
heat pumps can’t hold up in the extreme cold of an Upper Midwest
or New England winter.

Rocky Mountain Institute’s new Cold
Climates Addendum
, an update to The Economics of Zero-Energy
Homes, a report published in October 2018, aims to dispel the
notion heat pumps aren’t suited for extreme cold.

The report found that when air-source heat pumps or heat pump
water heaters are installed in a new home also outfitted with a
tight building envelope and rooftop solar PV panels,
electrification is economical even in regions with the harshest
winters.

“With today’s technology, cost-effective electrification for
residential new build is possible even in these cold climates —
even as cold as Duluth,” Alisa Petersen, report co-author and
senior associate, buildings team, RMI, told Greentech Media in an
interview.

“Electrification is possible, and it can be done in a way
where the utility bill is not increased for people in those
buildings,” she added.

“If you are a policymaker and you’re trying to meet your
climate action goals through electrification, you want to make sure
you’re also making it so that people aren’t paying more for
their utility bills.”

She went on, “If you do electrification in combination with
other deep energy efficiency measures such as building envelope
improvements and reducing the amount of infiltration going into
your building, then it actually can be more cost effective than
having a natural gas code baseline home.”

Moving beyond electrifying space-heating equipment

The RMI team first modelled code-compliant all-electric homes
versus natural gas homes in three cities with varying severities of
winter: Chicago, Illinois; Bozeman, Montana; and Duluth,
Minnesota.

They found that baseline all-electric homes cost less to build
upfront but more to operate in utility costs thereafter compared to
baseline natural gas homes.

But, the researchers wrote,
“you can tunnel through this economic barrier by pursuing deeper
levels of efficiency and adding solar PV.”

So, they added scenarios comparing natural gas baseline homes to
both electric zero-energy ready (ZER) and electric zero-energy
homes.

“In every instance, pursuing ZER homes was more economical
than just electrifying space-heating equipment with code-compliant
equipment, and in colder climate it actually changed the economics
of electrification from being painful to homeowners to being
beneficial,” they found.

Over 30 years, the economics of high-efficiency residential
electrification look even better. Electric zero-energy homes
performed better than either electric ZER homes or electric
baseline homes over the life of a typical mortgage, generating
added net-present value of $21,438 in Chicago, $14,072 in Bozeman,
and $19,018 in Duluth.

Getting it right from the start

Heat pumps were ripe for myth-busting. Air-source heat pump
technology has
come a long way
in the last 10 years, according to Petersen and
co-author Michael Gartman, also a senior associate on RMI’s
buildings team.

Technology improvements are reflected in RMI’s findings. The
report noted that cold-climate heat pumps can heat homes even when
outdoor temperatures dip to -12 degrees Fahrenheit and found that
supplemental electric resistance heating was needed just 3 percent
of the time in Bozeman and 10 percent of the time in Duluth.

The key is to buy the right equipment for your climate zone at
the outset.

“The colder the climate, the more important it is to make sure
you are finding the correct equipment when you are electrifying,”
said Petersen. “There are specific cold-climate heat pumps that
are made for cold climates. If you are just installing a typical
heat pump in a cold climate, then you’re not going to have
success.”

“We’re building 1 million homes every single year [in the
U.S.],” she added. “It’s always easier to electrify those
buildings from the start than to retrofit them later. When we build
new homes, we should build them right the first time because any
home we build now is going to be around in 2050.”

The importance of changing building codes

With heat pumps now a viable option in cold climates, Petersen
and Gartman urged manufacturers, policymakers and utilities to take
proactive measures to jumpstart the market.

“For obvious reasons,” said Petersen, “you need a bit more
than manufacturer promises. That’s exactly what we’re finding.
There are case studies in the real world in very cold conditions
where these are working.”

Even more important, she added, is that policymakers need to
adopt stricter building codes that raise the floor for electrified
buildings.

“Ultimately, most builders tend to build code-compliant
buildings,” she said. “If policymakers really want to drive
electrified buildings or net zero energy buildings, it will come
down to changing their building code. The codes are the ultimate
driver.”

She went on, “If we were able to convince city policymakers to
have written into their code that you can only do all-electric
buildings, that’s when you’re going to see ultimate change
where builders are going to have to figure out how to install
all-electric buildings.”

Also, utility decision makers need to recognize that
policymakers nationwide are
increasingly embracing building electrification
as a
decarbonization strategy
.

“The smart utilities realize that electrification is where
city and state policymakers are driving towards,” said Petersen.
“Utilities should be planning for the future and plan for how to
do building electrification the right way.”

Need for more thoughtful design

Petersen and Gartman conceded that getting electrification right
might require additional pre-construction planning.

“You do need to be a little more thoughtful in how you design
your buildings,” said Petersen. “The colder the climate, the
more thoughtful you need to be.”

She cited as an example the installation of residential heat
pump water heaters. In their modeling, Petersen and Gartman found
that in cold climates heat pump water heaters should be installed
inside the home, rather than the garage, for optimal
performance.

Installing heat pump water heaters indoors requires the builder
to set aside more space for the unit, but it also eliminates the
need for less efficient backup electric resistance heating.

If care is taken to properly select and site heat pumps, it
should help ensure that contractors, builders, and homeowners
don’t dismiss heat pumps based on a bad experience.

“It’s seeing more of these products actually installed and
having experience with it, and hearing the success stories, that
would make people feel more comfortable,” said Petersen.

“We’ve hit this point where heat pumps work even in the
coldest and harshest conditions in our country, and there’s no
reason we shouldn’t be pushing forward on all fronts,” added
Gartman.

Source: FS – GreenTech Media
Electrification Myth-Busting: Heat Pumps Are Ready for Cold Climates Today