heat pump vs. warm air furnace

FTWIII

I am a heating contractor who mainly deals with steam & hydronic boilers. From what I know about warm air furnaces is they make the rooms very dry and the house cools down quickly when the unit shuts off? Does this also hold try for heat pump heating systems?

meplumber

As usual, that depends....

Old style on/off furnaces and heat pumps did perform as you describe. However, there are units on the market now that are fully modulating and condensing. We are now using multi-speed fans and zoning controls to dramatically increase comfort.



I prefer the use of dual fuel systems for some buildings over traditional hydronics, even though I am a wet-head.



In ME, we have some of the highest electric rates in the country. But with a properly sized and installed dual fuel furnace we have seen some good things. Basically, the reversed cycle heat pump is utilized down to a set outside temperature and then the gas burner takes over. Nice systems.



Good Luck.

don_9

Envelope issue

Along with leaky air ducts are the reason for house being dry.Think about it for a second  when air is heated it expands causing the number of grains of water vapor to occupy a larger volume of air.Really matter not what type of heat plant that is being used however wetheat is alittle more forgiven only bc........ 

Tom Blackwell_2

envelope 2

As previously mentioned, the cause of dry air on forced air systems is because of the increased infiltration that is caused by the pressure differentials created by moving the air.

It has nothing to do with the heating air temperature-heat does not rid air of it's moisture content, only the ability to absorb it. The other factor-one that directly affects comfort is the influence of MRT (mean radiant temperature). In a forced air system the walls and ceiling stay fairly cool and absorb additional heat from the air during the off cycle, thus requiring an elevated thermostat setting to maintain the same feeling of comfort. The less cycling that is going on will result in better comfort, and the newer heat pumps with variable capacity do a good job of this.

FTWIII

Geo

The reason I am asking is I am looking into a Geothermal heat pump. My goal is to achive a very efficient, and comfortable system. I don't want to go through the expense of geothermal and not be comfortable.

don_9

Geo

Geo is a good way to go but it to suffer the same issue as any equipment when it comes to a poorly design building envelope.But being your discharge air is only going to be 30 degree above your entering air temps you have less issue with the air expanding.

If I may ask what is your heat loss verses your heat gain? If your heat loss is greater then your heat gain then you may have to add supplement heat.And usually with geo it done with electric heat strips.that could take you out of any saving you were hoping to see in the winter by going with geo.And please dont listen to the contractor that said your btus will not decrease as the outside temps go up or down bc ground temps stay constant.nothing can be further from the truth.

Food for thought.