Heater Strategy and Equipment advice.

May 27, 2020
6
MARYLAND
My 35000 gal salt water rectangular pool and attached spa -8x8ft are currently heated by a heat pump for the pool and gas heater for spa. The equipment was purchased in 2005. Natural gas spa heater just failed. I need advice on best heating strategy regarding equipment. One gas heater for both? Stay with heat pump for pool and gas for spa? Spa is on same filter pump as pool but separate plumbing circuit. If gas heat alone is the way to go, is there a brand preference? How would you set it up? I have the iAqualink control system and a Jandy controls. Aqua pure salt system. What equipment brand would you recommend?
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
19,756
Northern NJ
Welcome to TFP.

Post pics of your equipment pad.

Describe how you like your pool heated now? You happy with the HP heating your pool?

What are you electrical and NG costs?

What model gas heater and HP do you have?
 

Richard320

TFP Expert
LifeTime Supporter
Jan 6, 2010
23,930
San Dimas, CA (LA County)
Heat pumps don't put out enough heat fast enough to bring a spa up to temperature quickly when you want to use it. That's probably why someone installed a gas heater.

If you're going to buy a new heater, look for the same brand and model and check if the plumbing unions are still in the same spot. Then there will be no plumbing alterations needed. My
 
May 27, 2020
6
MARYLAND
Thank you. I am interested in strengths and weaknesses of Jandy, Raycom, Heyward etc. Is there a standout? I think changing to a a single 400000BTU natural gas heater to heat pool and spa would work well (eliminating the heat pump). Is that a good idea? Is there a brand that is best? If i have Jandy controls, is there a compatibility issue with equipment?
 
May 27, 2020
6
MARYLAND
Welcome to TFP.

Post pics of your equipment pad.

Describe how you like your pool heated now? You happy with the HP heating your pool?

What are you electrical and NG costs?

What model gas heater and HP do you have?
The heat pump worked just fine for 15 years. The gas heater was for the spa. I cant tell you the exact costs. The equipment is 15 years old - there must be some improvements by now?? The natural gas heater is kaput. Because I have to replace it, should I go with one system vs two?
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
19,756
Northern NJ
The physics of heating a pool has not changed in 100 years. HP and gas heaters basically are the same now as they were 20 years ago with a few efficiency improvements along the way.

Lots of folks here like the Raypak heaters.

 

U2brothr

Active member
May 19, 2020
36
Toronto, ON
I just bought a Raypak 266 BTU heater for my pool. I bought the digital one. I don't have a spa. Turn it on. It gives you the mode of choosing a temperature for your spa and a temperature for your pool. It lights automatically (no pilot to light yourself like a millivolt). When the water goes through the heater, it tells you what the pool temperature is and what the set temperature is. When the water reaches the temperature, the heater turns off. The heater also turns off when the pump is stopped.

So yes... get one for both... and get a digital one not a millivolt one (If you have a plug nearby).

One HVAC guy told me to go with a Jensen heater.... two other HVAC guys told me to go with the Raypak. The parts are readily available and they are easy to service. The exhaust is a flat hood.

I had to replace the 1980s Hayward heater that I bought the house with. In the winter, a squirrel made a nest in this monstrosity of a heater complete with chimney stack. It didn't light afterwards. So we had to get a new one.
 

PoolGate

Gold Supporter
TFP Guide
Jun 7, 2017
4,874
Damascus, MD
What temp do you like your pool at? Do you swim pre-season/shoulder months? Gas is the quickest way to heat but operating costs are high. Figure over $4/hour to run it. How large is your current gas heater? To upgrade to a 400k btu heater may require gas line heavy-up which could be a considerable expense.

Most heaters will work with most automation.
 

setsailsoon

Gold Supporter
LifeTime Supporter
TFP Guide
Oct 25, 2015
3,384
Stuart/FL
It's really very difficult to answer some of your questions without a few more specifics and an understanding of your personal preferences. But here's my best shot without that information.

Gas and heat pump technology haven't really changed much other than gas have gotten a little more efficient but not so much that they've closed the gap much for operating cost on a $/BTU basis. Gas is about twice heat pump on this basis. Heat pumps have much lower operating cost but they heat more slowly and cost more up front to purchase. Typical costs I've seen HP are about half the operating cost of gas heaters per unit of heat. Problem for a large pool is that heat pumps max out at about 130,000 BTU/Hr. Gas heaters max out at about 400,000 BTU/Hr. Heat pumps are much more expensive to purchase on a BTU basis. For example a 130,000 BTU/Hr heat pump is about $4000. A gas heater that's 400,000 BTU/Hr is typically $3000 (this is equipment cost not including installation). Also, heat pumps lose some of their efficiency advantage as air temp drops.

So what's optimal for you depends on how long you want your season to run, what pool temp you require, and the cost of electricity Vs gas in your area. It would appear to me your original design was optimized for a fairly short swimming season for the pool and a longer season for the spa. But that's just a guess on my part. If you purchase a 400,000 BTU gas heater and plumb it to run for both the pool and the spa it will definitely raise your pool temp quicker and extend your season but it will cost a lot more to operate because operating cost for a pool pump on a $/BTU basis is about twice as much for gas heat as heat pump. Also, your gas heater may have additional cost for the increased meter size and gas delivery line. You need to check your meter size to determine these costs.

As to control issues, there really aren't any. You can control any brand heater with any brand of automation. At the moment I believe Pentair offers the best automation capability but I don't really think its advantages are leveraging for control of heaters.

If it were me, I'd check the cost of upgrading your gas supply to accommodate a 400,000 Btu/hr heater. If this cost is low, I'd upgrade to a 400,000 BTU gas heater and keep the heat pump. If the upgrade cost to the gas system is very high I'd probably go with the maximum size gas heater you can without the gas line improvements, probably at least 250,000 BTU and keep the heat pump. You'd be able to extend your heating season and keep the pool comfortable much of the time with the heat pump after the gas heater gets you to temperature. Your gas heater would also heat the spa very quickly year round in very short order and maybe the heat pump could heat it some of the time at a much lower cost. But this is driven by the fact that we swim a lot year round and want both available. Hybrid systems have always seemed to make sense to me for a large pool or colder climates with a shortened season but I don't see many of them. Perhaps due to the up front installation costs.

Please keep in mind everything I've presented here is based on typical costs. Electric costs vary by about 3x across the country and delivered gas costs vary as well. This can dramatically change the conclusions you would draw.

I hope this is helpful.

Chris
 
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May 27, 2020
6
MARYLAND
The physics of heating a pool has not changed in 100 years. HP and gas heaters basically are the same now as they were 20 years ago with a few efficiency improvements along the way.

Lots of folks here like the Raypak heaters.

Thanks. Would you convert a dual system to one gas heater?
Paul
 
May 27, 2020
6
MARYLAND
It's really very difficult to answer some of your questions without a few more specifics and an understanding of your personal preferences. But here's my best shot without that information.

Gas and heat pump technology haven't really changed much other than gas have gotten a little more efficient but not so much that they've closed the gap much for operating cost on a $/BTU basis. Gas is about twice heat pump on this basis. Heat pumps have much lower operating cost but they heat more slowly and cost more up front to purchase. Typical costs I've seen HP are about half the operating cost of gas heaters per unit of heat. Problem for a large pool is that heat pumps max out at about 130,000 BTU/Hr. Gas heaters max out at about 400,000 BTU/Hr. Heat pumps are much more expensive to purchase on a BTU basis. For example a 130,000 BTU/Hr heat pump is about $4000. A gas heater that's 400,000 BTU/Hr is typically $3000 (this is equipment cost not including installation). Also, heat pumps lose some of their efficiency advantage as air temp drops.

So what's optimal for you depends on how long you want your season to run, what pool temp you require, and the cost of electricity Vs gas in your area. It would appear to me your original design was optimized for a fairly short swimming season for the pool and a longer season for the spa. But that's just a guess on my part. If you purchase a 400,000 BTU gas heater and plumb it to run for both the pool and the spa it will definitely raise your pool temp quicker and extend your season but it will cost a lot more to operate because operating cost for a pool pump on a $/BTU basis is about twice as much for gas heat as heat pump. Also, your gas heater may have additional cost for the increased meter size and gas delivery line. You need to check your meter size to determine these costs.

As to control issues, there really aren't any. You can control any brand heater with any brand of automation. At the moment I believe Pentair offers the best automation capability but I don't really think its advantages are leveraging for control of heaters.

If it were me, I'd check the cost of upgrading your gas supply to accommodate a 400,000 Btu/hr heater. If this cost is low, I'd upgrade to a 400,000 BTU gas heater and keep the heat pump. If the upgrade cost to the gas system is very high I'd probably go with the maximum size gas heater you can without the gas line improvements, probably at least 250,000 BTU and keep the heat pump. You'd be able to extend your heating season and keep the pool comfortable much of the time with the heat pump after the gas heater gets you to temperature. Your gas heater would also heat the spa very quickly year round in very short order and maybe the heat pump could heat it some of the time at a much lower cost. But this is driven by the fact that we swim a lot year round and want both available. Hybrid systems have always seemed to make sense to me for a large pool or colder climates with a shortened season but I don't see many of them. Perhaps due to the up front installation costs.

Please keep in mind everything I've presented here is based on typical costs. Electric costs vary by about 3x across the country and delivered gas costs vary as well. This can dramatically change the conclusions you would draw.

I hope this is helpful.

Chris
Very helpful Chris.
Paul