Heat Pumps: A Primer for Builders and Buyers
Heat pump systems seem to be everywhere now. If you or your clients are feeling confused by conflicting information, here’s an up-to-date guide.
As with everything else these days, there seems to be a growing disinformation buzz about heat pumps. Are they amazing or overhyped? Suitable for primary HVAC or only as a backup? Is a window air conditioner the same as one of the new window heat pumps?
In this article, I’ll drill into some of the key facts you need to know when thinking of adopting heat pump technology.
What Are Heat Pumps?
Let me begin, however, with a bird’s eye view. The effectiveness of any heating or cooling system relies on the quality of the construction. No piece of mechanical equipment can “fix” a broken building envelope, where uncontrolled air leaks in and out through cracks and gaps. The tighter, better insulated your building, the better heat pumps are going to handle your indoor comfort, no matter what climate zone you live in.
So if you’re asking, “Can heat pumps do the job,” you’re asking the wrong question. A better approach would be, “Is my house ready for heat pumps?”
Heat pumps pull heat from the cold outdoor air and transfer it indoors. In warmer months, they pull out heat from the air indoors to cool a home. Heat pumps are powered by electricity and don’t burn fossil fuel like furnaces do, making them more environmentally friendly.
Heat pumps do a fantastic job managing energy and redistributing it in the form of heat into your home, but they tend to produce BTU output much lower than that of forced-air furnaces, boilers, or wood stoves. So you need to make those BTUs count.
Heat Pump vs. Air Conditioner
A common question is how heat pumps differ from air conditioners. Both systems can cool air in your home, but only a heat pump can also provide heat. This dual functionality makes heat pumps a more versatile option, especially in climates with cold winters.
However, it's important to note that not all products claiming to use "heat pump technology" are created equal. Some types of heat pumps use inefficient electric resistance heating to provide heat, which can lead to higher energy costs.
Why Convert to a Heat Pump? Pros and Cons
Let’s assume for a moment that you live in a bubble where Climate Change hasn’t affected you directly. Maybe Newfoundland? You’re content to leave reducing CO2 pollution to everyone else, so you plan to keep burning gas, coal, wood or oil.
I can still think of 6 good reasons you may want to switch to a heat pump.
Pros of converting to a heat pump
- Energy Efficiency: Heat pumps transfer heat instead of generating it. This means that on a “cost per BTU basis,” they use a lot less energy, especially for heating, when compared, for instance, with traditional electric resistance baseboard heaters.
- Rebates: Rebates and incentives can offset the initial cost of installing heat pumps. This labor cost has been dropping in recent years, and DIY products have begun to hit the market as well.
- Ductless Installation. By not having to leave wide open cavities for ducts inside your walls and floors, you reduce labor, materials and noise inside the home.
- Safety: Unlike gas or oil furnaces, heat pumps don't burn fuel to generate heat, eliminating the risk of carbon monoxide poisoning, explosions, and fires.
- Versatility: Heat pumps can both heat and cool a home, providing a two-in-one solution that saves on maintenance and installation.
- Longevity and Durability: Heat pumps typically have a longer lifespan compared to traditional HVAC systems. They also have fewer mechanical components, which can reduce the frequency and cost of repairs.
However, not every home is ready for heat pump conversion. I can think of three scenarios where you might be disappointed by new heat pumps. You need to add other efficiency upgrades first.
Cons of converting to a heat pump
- Shoddy insulation. If your attic, basement and walls lack adequate insulation and sealing, your heat pump may struggle to make the home comfortable. Get an energy audit, fix leaks and insulate first.
- Rabbit Warren Floorplan. Heat pumps are ideal for more modern, open floorplan designs. In an older home, with a galley kitchen for instance, you will need multiple “head” units to distribute heat or cooling. You may end up spending more than you want unless you can figure out a way to move conditioned air efficiently around the home, typically with a custom ventilation system. For example, Panasonic offers a suite of ventilation products controlled by a SelectCycler smart device that would make that possible.
- Unreliable Grid. If you live in an area with frequent power outages and extreme weather, heat pumps don’t provide as much emergency resilience as, for example, a propane boiler. That being said, if the home already has an existing oil or gas heating system, you can leave it in place as a backup and install ductless heat pumps without any “deconstruction” of the old HVAC. You could also install a battery backup and/or a solar array.
This brings me to my final point. Air source heat pumps are hands down the best option right now for getting our homes off fossil fuel dependency, with the possible exception of ground source heat pumps.
Heat Pumps for the Future
Heat pumps can and will run on solar as an energy source, both directly and indirectly. New models, just hitting the market, can run off either solar panels directly or your home’s grid-tied power. But if you install a solar array on your home, all heat pumps are running directly off that power when the sun is shining and likely burning your accrued credits when it’s not.
That’s really the point. It’s the reason so many of us are pushing the rapid adoption of heat pumps for home heating and cooling systems in housing. The faster we get to fully electric living, the sooner we can close the valve on fossil fuels and begin to undo the century of cataclysmic change we’ve caused to Earth’s weather patterns.
Heat Pumps: Glossary of Terms
Understanding heat pump terminology can help you make an informed purchase:
BTU (British Thermal Unit): This is a unit of heat energy. One BTU is the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit.
Coefficient of Performance (COP): This measures the efficiency of a heat pump by comparing the energy output to the energy input.
Compressor: This is the part of a heat pump or air conditioner that compresses and pumps refrigerant to cool your home.
Condenser Coil: This component releases heat into the outdoor air when the system is in cooling mode.
EER (Energy Efficiency Ratio): This measures the energy efficiency of a cooling device at a specific outdoor temperature.
Evaporator Coil: This component absorbs heat from your home's air when the system is in cooling mode.
HSPF (Heating Seasonal Performance Factor): This measures the efficiency of a heat pump in heating mode. The higher the HSPF, the more efficient the heat pump4.
Refrigerant: This is the substance that absorbs and releases heat as it circulates through a heat pump or air conditioner.
SEER (Seasonal Energy Efficiency Ratio): This measures the cooling efficiency of a heat pump or air conditioner. A higher SEER rating means greater energy efficiency.
Ton: In HVAC terms, a ton measures a unit's cooling capacity. One ton equals 12,000 BTUs per hour.
Window Heat Pump: Heat pump technology is now being used in window unit air conditioning as “spot” conditioning.