using both heat pump and gas heater, please help

[staycation]

Hello all, especially plumbing and heating experts:
I am building a pool/spa via the owner-builder route. So far, it has been a steep learning curve and this forum has been an invaluable resource. I am running into another problem that I hope some one here can help. How to run a HEAT PUMP and gas HEATER together to heat a pool and spa. Believe it or not my plumbing and heating consultants have not done anything like this in Northern California. I will be using the Intellitouch Dual-Heat module.
Questions:
1. If you have a similar set-up, can you tell how yours is set-up?
2. What relay and temperature sensors do I need and where to put them?
3. I would like to set it so that the heat-pump will do most of the heating and use the gas heater either manual or automatically (intellitouch) to kick in as back-up. Is this possible?
4. Any other information is greatly appreciated?

Thanks so much!

 

[PoolOwnerNumber9]

Why do you want to use both?

 

[staycation]

it's like using both solar and gas.
the heat pump is very efficient and is a cheaper way of maintaining a warmer pool temperature.
Gas for quicker heating when needed.

 

[PoolOwnerNumber9]

Can you post your calculations for energy costs to run the heat pump vs. the gas heater? I would be surprised if the heat pump really was cheaper to operate.

 

[JasonLion]

Heat pumps are much less expensive to operate than gas heaters in most parts of the country. There are areas with extremely high electric rates where that isn't true, and heat pumps are not very good at low air temperatures, but for the most part a heat pump costs significantly less to keep the pool warm.

The IntelliTouch comes in various models, most but not all support two heaters. Setup is fairly simple, just configure the IntelliTouch to recognize both heaters and set it to H PUMP PREF mode and you should be all set. All you should need are the standard air and water temperature sensors.

 

[PoolOwnerNumber9]

Jason, I had thought that gas heaters were more cost effective. What is the approximate cost per delivered BTU for a heat pump vs. a gas heater?

 

[JasonLion]

The US Department of Energy has a good comparison of the cost of different kinds of pool heaters in different areas of the country here.

The actual cost per BTU varies with several factors, air temperature, cost of electricity, efficiency of the heat pump, etc. In typical situations a heat pump costs less than half as much as natural gas, but it varies by region and time of year.