Page 26 - GB Building Science Ebook 2019

04 HVAC: CHANGING WITH THE CLIMATE

The limitations of heat pumps are that they perform most
efficiently within an optimal temperature range—not too cold or SHIFTING POWER
hot. But manufacturers continue to tweak the technology to operate
at ever more extreme temps. WHERE IT BELONGS
A rapid retooling and expansion of heat pump technology is taking
place behind the scenes at many of the big HVAC manufacturers.
Each iteration of product is better. For example, Carrier has fine
tuned its Infinity line of heat pumps to reduce noise levels, thanks
to a variable speed motor that ramps up, rather than kicking on at
full speed.

AN EFFICIENCY FEEDBACK LOOP
Some homeowners have been surprised to find that their new heat
pumps are not saving as much money on HVAC as they expected.
This observation usually points back to the efficiency of their
building, not a flaw in the HVAC technology. A new awareness of
their envelope’s poor performance often leads to energy upgrades
such as new windows and additional attic insulation—resulting
(albeit with some pain) in a more efficient home and lower monthly
utility bills.

ELECTRIC BASEBOARD

HEAT vs HEAT PUMP

Electric Heat Heat Pump

Quick to heat up space Slower to get to temp
Not whole home coverage with one
Zoned EVADA’S 2019 NV Energy, a subsidiary of Berkshire
machine Hathaway Energy, has taken an aggressive approach
to bring both homes and businesses closer to zero net
Rather expensive (1:1) Low cost of operation (3:1) N energy performance. Their long term strategy is fairly
Heat and cooling spreads throughout SOURCE: SUNSHINE RENEWABLE ENERGY transparent: They aim to be ahead of the curve as fossil fuels phase
Heat doesn’t spread well
space out, not playing catch-up. To that end, they’re building some of
Offers AC and dehumidification the largest solar arrays in the U.S., at the same time helping their
customers upgrade to more efficient air conditioning, helping them
Quantum Leap. Heat pumps have made electric heat much more install and understand smart thermostats, and offering free energy
economical and comfortable. assessments to homeowners. They also address major energy-using
appliances and electronics in the home, including lighting and pool
This new awareness of a home’s inefficiency occurs on the pumps. This mission extends into the business arena as well, where
comfort level as well as the financial level. Homeowners have high they offer cash incentives to help businesses upgrade equipment
expectations from their heating systems. Gas and oil furnaces tend efficiency.
to heat rooms extremely quickly, creating a massive blast of energy. Most of this proactive assistance falls under a program called
Electricity doesn’t offer that kind of instant firepower. This is why PowerShift, NV Energy’s multi-faceted approach to reducing the
instant on-demand electric hot water systems never caught on in the power load required by each customer.
U.S. The initial massive surge of electricity would cause lights to dim Why would a utility want to sell less electricity? First, it’s the right
in the house, and put a heavy load on residential power supplies. thing to do, and NV Energy has a strong sustainability commitment.
Retrofits will be needed in millions of existing homes to make Second, the economics add up. With reduced demand, NV Energy
the leap to renewable electricity and especially HVAC. But going will be able to meet the goal of 50% renewable power much sooner,
forward, it’s important for the industry to embrace zero net energy without the need to construct interim fossil fuel plants. They can
construction quickly. A house with 2 ACH is far easier to heat and transition straight to solar PV with battery storage and minimal
cool with heat pumps than a conventional one at 5 ACH. Putting disruption of services. It’s an approach that makes good business
solar panels on a leaky house will give solar an undeserved bad sense and also makes the company more resilient.
reputation.

26 BUILDING SCIENCE SPECIAL REPORT: SIX WAYS CONSTRUCTION IS CHANGING