Around this time each year we start getting this question alot as people start looking at air conditioners and hear that they should consider a heat pump. All you wanted was some A/C to give you relief from the heat, why is some saleman telling you that you should consider a heat pump?
Well lets start with what these names mean. An Air conditioner, as we call it without even thinking about it, is a piece of equipment we know to cool the temperature of a space. So why not air cooler? When we look at how an air conditioner works it really is a fitting name. Saying it cools the air is selling an air conditioner short. One of its most important jobs is humidity control. Air conditioners dry the air inside your house. This is important because dry air feels cooler and keeps you from feeling sweaty. Warm air holds more moisture than cool air, so as the freshly dried and cooled air starts warming back up in our home it becomes “thisty” for more moisture. This effect accelerates our bodies own cooling system leaving us feeling cool and dry. By controlling both temperature and humidity Air conditioners really are conditioning that hot summer air.
Ok so how about Heat Pumps then? Heat pumps get their name from what they do. Through condensing and evaporating of a refrigerant in a looped system, heat pumps literally pump heat from one place to another. Ait conditioners work in this same way but only pump heat from inside to outside. The difference is that a heat pump can pump both ways. They are able not only to pump heat out of your house in summer, as an A/C does, but pump heat into your house in the winter.
Short answer is A/C = cooling and heat pump=cooling and heating.
Now back to the salesman. Why is he trying to sell me a heat pump when I already have heat and just want cooling? Truth is, He may not just be trying to get an upsell. In most cases a heat pump makes much more sense then an air conditioner. This is for the simple reason that heat pumps pay your back in a decreased heating bill, and over time will pay for themselves, while an A/C will only add expense. Here’s why, One cubic foot of natural gas holds about 1,000 BTUs of heat, one cubic foot of propane has about 2,500 BTUs and one killowatt of electricity puts out 3,200 BTUs. These values are absolute and represent an unreachable 100% efficiency. No matter how efficient your furnace, air handler, or boiler is, it cannot exceed these numbers. This is because these units are generating heat using those fuels and those values represent the maximum retrievable energy each one holds. As the name implies though, heat pumps use their energy to move heat from one place to another. By moving heat rather then generating it, a heat pump can put over 13,000 BTUs into your home for every killowatt used. Believe it or not there is enough heat in the air outside to heat your home all the way down to negative 10f.
So this summer when you start to consider an air conditioner. You might want to spend the extra little bit and get the heat pump.
I have a boiler system that provides baseboard heat to two floors in our home. Each floor has it’s own zone. I have already purchased a 3 ton heat pump with intent to install it in my attic with ample registers to cool the upstairs and plans for two runs to the first floor with hopes to cool the entire house from the top down. I’m in western Pennsylvania and we don’t get a lot of hot weather. My intent was to use the heat pump primarily for cooling. If I just use the heat pump for air conditioning will I have greater energy efficiency over a regular AC unit? I read your article on HEAT PUMP VS AIR CONDITIONER and it was explained that the heat pump is much more efficient when used for heating. Is it more efficient when it comes to cooling? I also thought a heat pump was a good idea for emergency heat if the boiler were to break down or to supplement the boiler system. A local AC guy told me that if I used the heat pump to supplement the boiler heat system it would most likely interfere with the boiler system. He recommends a regular AC unit to do cooling only and heat with the boiler. Your answer to the cooling efficiency of an AC unit versus a heat pump and your thoughts on supplementing the boiler system would be most appreciated.
Hi Robert, thanks for the question. Heat pumps are not more efficient then ac units for cooling. In fact, the SEER rating, or seasonal energy efficiency rating, that is used to express the efficiency of a heat pump or ac system, is a rating of cooling efficiency. So a 13 SEER heat pump will use the same amount of power to cool as a 13 SEER air conditioner.
There is no way adding a heat pump would interfere with you boiler system. In fact in our area the local power company recommends people keep their radiant heat as supplemental or emergency heat when upgrading to a heat pump. You didn’t mention what heat source your boiler uses but the heat pump most likely will be a cheaper source of heat for your home.
Let me know if you have any other questions,
Cory
I had no idea that heat pumps operate by condensing and evaporating a refrigerant in a loop system. That is awesome that heat pumps are a very efficient way to heat and cool your home. I like that heat pumps also work well at supplementing your boiler system! Thank you for sharing the benefits of having a heat pump in your home!