Thoughts and Tips from a Believer
For those of you who know Juneau resident and heat pump believer Shawn Eisele, you know his passion for experimentation, for learning, for digging in to better understand what works and what works best. Shawn applies this disciplined approach to ski tuning, to program marketing, and most recently, to heat pump functionality. Shawn has generously shared with Alaska Heat Smart his latest thoughts on heat pump heating and some ways in which heat pump owners can extract more heat from these amazing devices. This seems like pretty appropriate reading material given our current chilly October temps! Thank you, Shawn!
“My Heat Pump Isn’t Keeping Up” – But It Probably Can!
Courtesy of Shawn Eisele
If your heat pump is set at 75, but your house temperature is barely 65, we have good news – your heat pump can probably produce more heat – it just needs to be told to do so. A few simple adjustments can help.
Most commonly, the heat pump isn’t being maxed out. Rather, it thinks it’s producing enough heat, even though you may think otherwise. The heat pump’s thermostat is located on the air handler where all the hot air comes from. This thermostat measures adjacent hot air so if air circulation in the room is inadequate, the heat pump doesn’t understand that it should produce more heat. The heat pump coasts along on easy street, believing it’s 72 in the room (or whatever the remote is set to), but the adjacent room is ten degrees cooler.
Yes, you could just crank up the temperature setting on the remote. You might need to crank more than expected, say to 74 so a further away part of the house warms to 68. But to really make your heat pump work well and do so efficiently, you need to boost its air circulation. First, on the indoor unit(s) of your heat pump, set the fan to medium-high or high so the hot air produced moves into the rest of the house. Then, direct the louvers of the air handler to where you want the warm air to go. Is most of your living area off to the right? Then direct the hot air a bit to the right. Generally, direct the air just lower than horizontal. You want it to move directly out and away from the heat pump. Move obstructions out of the path of air flow. If there is a coat rack or table blocking the air, move it out of the way and let the air move easily from your heat pump to other parts of the house. And speaking of circulation, if you haven’t cleaned your filters recently, do so now! Unimpeded air flow will not only improve heat circulation, it will save you money.
The next major change you can make is to improve circulation in the room generally. A ceiling fan running in reverse can pull cooler air up from the floor and back to the heat pump’s air handler. Or, you can add a standing or desk fan to blow air from the cooler part of your home (say low on the floor, from a cold room or below a picture window) up towards the air handler. That cooler air not only tells the heat pump that more heat is needed, it also makes the heat pump more efficient, since it’s easier to heat cold air than hot air. If your air handler is near the ceiling, moving cooler air to it might make the biggest difference of all.
You can, by the way, install a separately-purchased heat pump thermostat in a different room, so the heat pump really knows it needs to keep producing heat. Still, increasing circulation and providing cooler return air is important to making even that set-up more efficient.
When outdoor temperatures drop, avoid setting your remote’s thermostat down at night. Instead, consider closing or mostly closing doors to bedrooms and spare rooms you don’t need overly warm. Reducing the square footage to heat at night, the time when it’s coldest and hardest to produce heat, will keep the heat pump’s warm air flowing to those spaces that you’ll want warm in the morning. That’s great because on cold days the heat pump won’t have capacity to warm them up as quickly in the morning. Later, open the bedroom doors when the sun is out and it’s easier for the heat pump to produce heat. CAUTION: If you have an oil boiler and hot water (hydronic) baseboards in your home, be sure to not cool certain rooms too much to prevent pipes from freezing. The same applies to plumbing in bathrooms.
Attention needs to be given to the heat pump’s outdoor unit (compressor) as well. Make sure there’s an abundance of air flow around the compressor. Is snow covering half of it? Get rid of that. Is the copper refrigerant line uninsulated and giving off heat? Insulate it and save that heat for inside. Hopefully the compressor is far enough off the ground so it’s not touching the glacier of ice forming below it. (When a heat pump gathers heat from the air, the compressor becomes very cold and humidity freezes on it. A defrost cycle melts this frost and drains below, forming ice.) Good projects to schedule for next summer are to construct a roof over the compressor to shelter it from rain and snow. Ensure there is a clear path for water to drain below an elevated compressor. You can have a technician install a drain pan heater at the bottom of your unit, so water flows through instead of freezing there. Most installations today have this as a standard feature, or at least a highly recommended add-on.
By the way, it’s a little late to mention this, but hopefully you’ve installed a heat pump designed for colder climates. Daikin’s “Aurora” line and newer ‘Atmosphera’ line are rated down to -13°F and Fujitsu’s “H” models are rated down to -15°F. If you don’t yet have your heat pump installed, be certain that your quoted equipment is cold climate ready!
Ultimately, a heat pump struggles to gather heat when it’s really cold outside, and unfortunately that’s when you need the most heat. Having a back-up heat source to provide supplemental heat on cold days is important. This might mean retaining your old Toyo, furnace, or boiler for frigid days, or installing a wood stove or electric or IR baseboard heaters. Luckily, Juneau is rarely frigid, allowing us to get the most out of our heat pumps on these cold, but not frigid days. A heat pump may require a bit more thought and tinkering than our outdated oil-burning systems did. The savings seem worth it!
In summary:
- clean your indoor air handler’s filters
- ensure the outdoor compressor is clean and has unobstructed air flow
- when cold, use an auxiliary fan to direct lower cool air up to the air handler
- increase the fan speed, especially at night
- if you have a floor unit, switch the air flow to the top outlet only to increase air circulation
- close doors to room that do not need to be overly warm, being thoughtful about freezable pipes
- keep your remote control mode set on ‘heat’, never ‘auto’