Back Up Heat Source and Boosting Loop Temps

[stevehull]

Wewant,

Yes, the use of electric resistance strips is common. In fact, all "electric" furnaces are just that - a resistance strip in a non-combustible box.

Please note that I am NOT advocating putting a small electric stove top bread toaster in the return or supply air flex duct!

Most commercial GT heap pumps have space for a resistance heater that is often called "emergency heat". But your electric resistance range oven has exactly the same.

Many people in southern Florida have no home heating units - just AC units. On those few days when it gets cold, just turn on the electric oven, bake some bread, or just leave the oven door open with the baking element turned on. Again note, this is NOT for a gas oven!!

In your area you have far more heating than cooling days. So to keep a home adequately heated, you may need for example a four ton heater (48,000 BTU). But your cooling needs may only be a fraction of this - say 12,000 BTU (1 ton). Most HVAC systems that are one compressor speed will give you four tons of heating or cooling.

If your cooling load is low, as in your area, your AC system will only run for a small part of the time and you end up with cool, "clammy" air in the home in the summer.

This is why a multi-speed compressor is essential that can run on two tons or four tons. Or put in a split system. One example we refer to is the infamous "window shaker" (window AC unit). They cycle on and off, are loud, are inefficient, but are cheap.

AC also is correct to check your gas bill for the last month as you can estimate just how many BTUs it took to keep the house warm in the last month (very cold weather).

But don't think this is long range planning! Get a blower door test done now and then button up. Small amount of $ and some labor can decrease infiltration by easily 50%. This lowers heating cooling bills by 50% right there.

To get back to your original question, it would be silly to preheat the well water by heating it with resistance heating in order to get better efficiency from the GT heat pump. Your water temp is about 40 F and there is a LOT of heat in that water.

A lot of commercial GT heat pumps have a COP of 5 or higher, so think of that.

Have you considered an open loop system? In your area, a lot of people do that and then fill a small pond with water. This lowers your insurance rate (if you don't have local fire hydrants) and you can then irrigate from it in the summer.

You may already be on a well, so all you need is a slightly larger well pump.

Gotta agree with Randen - button up!! You may have lots of insulation, but you gotta check INFILTRATION. A super highly insulated box is worthless when it has a big hole in one end. Get a blower door test.

Steve