Does a heat pump make sense in Woodbury?

It seems that the news media is constantly putting out articles about electrifying the country and changing the way we heat our homes, going from fossil fuels over to electric heat pumps.

I have noticed much of the information being presented is lacking in details and in some cases promoting unrealistic expectations of what a heat pump can actually do.

A heat pump will cool your house in the summer and heat it in the winter.

In order to determine if a heat pump makes sense, we need ask what kind of benefits are we looking for.

We can make a list and check each item to see if a heat pump will be better than a natural gas furnace or if the furnace has the advantage.

Woodbury has mostly natural gas furnaces so we will not compare propane or oil burning furnaces.

Here is a list of items to check.

1. Better for the environment
2. Lower operating cost
3. Lower initial equipment cost
4. Better comfort
5. Ease of maintenance

The heat pump wins on the first item. If solar or wind is used to generate the electricity, then the air will not be polluted and carbon emissions will decrease. Our electricity is provided by Xcel Energy and they are increasing the percentage of both wind and solar power.

The next item, "lower operating costs", will take some investigation.

First we need to understand that as the outside temperature drops, the efficiency and output of a heat pump also drops while the efficiency of a furnace is constant regardless of the outside temperature. Also when the outside temperature goes too low, the heat pump will not put out enough heat to keep the house warm and then the furnace will have to take over.

This point where the heat pump is no longer able to maintain the desired temperature in the house is called the balance point. The balance point will vary depending upon the size of the heat pump and the output with the outdoor air temperature.

Bigger is not better. The size of the heat pump needs to be sized according to the amount of cooling needed in the summer. The reason for this is that oversizing in cooling mode will have bad effects.

If the heat pump is too large, in cooling mode it will cause high humidity levels in the home and be uncomfortable. Also the short cycling is hard on the compressor and may shorten its life.

We will use for an example a fairly common size house that needs 27,000 BTUs of cooling on a hot summer day and 60,000 BTUs of heating on a cold winter day to make the house comfortable.

The reason for the big difference in BTU ratings between heating and cooling is the larger temperature variance of the outdoor and indoor air in summer vs winter.

Using this example, we need a 2-1/2 ton size to properly cool this house.

By using the output data from the manufacturer we can determine that this heat pump will produce about 1/2 of the total heat needed for the house. The other 1/2 will have to be supplied by the furnace.

The current cost of energy heat output produced by running the gas furnace and the heat pump is shown in the bar graph. This is with a high efficiency heat pump and a 96% high efficiency furnace.

The difference about 10% less for the cost to heat your house with the heat pump during the time that the heat pump is heating the house vs the time the gas furnace is heating the house. This cost savings is just for the energy consumed and does not take into account the cost of the equipment and installation.

So the operating cost winner goes to the heat pump but the difference is not large. The energy prices change constantly so this difference may vary over time.

What about the initial equipment cost? It will vary from dealer to dealer but it can easily be 50% more expensive to purchase the new equipment for a heat pump system over a gas furnace system.

The comfort level is normally higher on a furnace than a heat pump. The reason for this is the air coming out of the registers is higher on a furnace. The less warm air from a heat pump can feel drafty to some people.

Your furnace or heat pump will need maintenance or repairs from time to time. In order to check the level of the refrigerant charge the heat pump needs to run in cooling mode and this has to be done in warm weather. So a technician may not be able to determine if the refrigerant is low until the warmer months.

I hope this will help you to determine which heating system is right for you.

My name is John Schuebel. I own Schuebel's heating and have been in the business since 1987.

schuebels.com