Gas v. Electric Heater- Time is of the Essence to Decide :)

cgtx

Active member
Jul 23, 2018
33
Austin/TX
Hi! First post here and please excuse my brevity, but we are in the middle of a (an in ground) build, and I need to tell my builder ASAP (imminent) whether to stay on track with our gas heater that is already plumbed or whether to rush to call electrician and plumber back to site to keep us on track to pour on Friday. QUESTION: How much better do you find gas heaters than electric heaters to be for heating spas and pools? The builder used a gas heater in his plans due to its superior efficacy over electric ones. The problem is that the pool equipment can not be on the side of the house with gas (due to windows) and is, instead, a bit awkwardly placed on the path between the house and the pool, narrowing the path and creating a space which we then must fence. Gas requires running/ trenching a gas line halfway around the house (currently pool equipment is on the left side, the gas is on the right side and all the way back toward the front of the house). Plumbing is already done.

If we ever do the home remodel I'd like, I would put windows toward the back yard where currently the pool equipment is supposed to be, IF I DECIDE NOW to switch to electric and give up the convenience of a much more rapid gas heater.

We can switch to electric and move the awkward equipment pad to the side of the house for more money, will have to increase electrical for the increased amps, etc. This can be done if he reroutes his crews and can still keep on track for shooting gunite soon... for $6000 more, but we lose the heating power.

If you have electric heaters, do you find them to be annoyingly slow? I don't want to give up how often we can use our spa and heat our pool in the winter for aesthetics, though I do hate that the way it is now, my kids would have to walk a fairly narrow path to get to the deep end and jump (their favorite thing), and that I could never punch windows facing out toward the backyard (we never use the ones on the side because they just go to the fence).

Anyone have strong opinions about gas v. electric heaters? I don't have the gift of time, and I know it is still in the middle of the workday for many, but desperate choices call for desperate posts. :) Thank you in advance! I will work on a new build post soon. (for anyone needing to know size of pool, it is 14 x 14 in the interior- not including coping- long rectangle with sunken spa and sun ledge on the shallow end)....
 

lager1829

Gold Supporter
Jul 8, 2015
146
Lancaster County, PA
I was about to comment that gas gives you a longer season due to the heat pump losing efficiency 60F and below, but I'm not sure that applies in Austin. True though gas are much quicker to temp.
 

Homebrewale

Well-known member
Apr 21, 2020
230
Apex, NC
I only have experience with a heat pump. We chose it because my wife swims laps every morning during pool season. I have found that the temperature, especially during spring and fall with cooler night temperature, will drop several degrees overnight even with a solar cover on the pool. My wife is sensitive to water temperature. I would hate to think what my gas bill would be if I had to heat up the pool every morning so she could swim. The heat pump is pretty economical for maintaining temperature. Yes, it can be annoying slow to come up to temperature when I first open the pool or reheating the water if we get a significant rainfall.
 

JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
17,220
Tucson, AZ
If the pool has a spa then you are going to find that the heatpump is annoyingly slow. My 400kBTU gas heater can get the 650 gallon spa hot in under 20mins. A heat pump would take well over an hour.

Honestly, it sounds like your pad is not being placed where you want it and that some very crazy trenching is being done to compensate. Are you willing to pause the job, take a hit to the schedule and rethink this? Are there any other accessible locations to tap the gas from around the house? Can you utilize a shorter, higher pressure line (smaller diameter pipe) with a regulator at the gas heater? Honestly it’s hard to envision what you’re talking about with pictures.
 

cgtx

Active member
Jul 23, 2018
33
Austin/TX
Thank you so much for replying!!! I do hate where the equipment pad is going, but I am trying to determine what I may lose/ compromise by switching to electric v. gas and moving it. It sounds like heating the spa on demand is much quicker with gas, but I was unaware that keeping the pool heated during cooler months may actually be better served with electric rather than gas... Am I right in understanding that gas is superior for "instant gratification" more sporadically, and electric is preferred for more constant but more- planning- required heating?
 

Homebrewale

Well-known member
Apr 21, 2020
230
Apex, NC
When I made the decision 14 years ago, it was due to operating cost. Natural gas before fracking was more expensive back then. Doing some back of envelope calculations back then, it was more economical to run a heat pump than a gas heater. I don't know if that is the same today. For a heat pump, it is important to use a solar cover to retain heat so it isn't running all the time.
 

wireform

Silver Supporter
In The Industry
Aug 15, 2017
1,483
Spring Valley, NY
Firstly I think you need to find out the running cost of gas and electric per hour and then the temp rise for each to determine which way would be better. Then the location issue may not come into question anymore say you decided on electric.
 

Homebrewale

Well-known member
Apr 21, 2020
230
Apex, NC
How slow are you talking? thanks
That depends on the size of the heat pump. With my previous heat pump that was sized barely big enough for the pool, it could take two weeks at season opening to bring the temperature from mid 50F to 86F which is what my wife likes as a minimum temperature. I have a newer heat pump that has a much larger BTU output than the previous heat pump. It only takes about 3 days now to raise the temperature at opening. During the spring and fall when I get over an inch of rain, the cold rain water can drop the pool 5F or more. It may take several hours to heat. For a temperature drop of 2 or 3 degrees overnight, it may take an hour or two. I usually don't notice the times much because if the water temperature has dropped significantly since the previous day, it's likely I don't want to use the pool. I'm not much into using the pool if the air temperature is below 80F.
 
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cgtx

Active member
Jul 23, 2018
33
Austin/TX
Firstly I think you need to find out the running cost of gas and electric per hour and then the temp rise for each to determine which way would be better. Then the location issue may not come into question anymore say you decided on electric.
Thank you! I was mostly trying to understand whether people who have electric heaters truly do not like them or find that they use their pool and spa less since my builder says the gas takes so much longer to heat and requires much more planning (I only knew his viewpoint until you all began commenting). I would live with location if electric heaters are prohibitive to being able to enjoy the pool and spa. From searching a great deal through this site, it seems that there are strong opinions both ways and that the pros and cons of both are so very different and not as clear cut as I'd hoped. I am grateful for the comments.
 

jark87

Silver Supporter
Jun 5, 2011
210
Flower Mound, TX
I’ll respond from a little different angle. We have a gas heater and are in virtually the same climate (Dallas area). We seldom use the heater, and when we do, it’s only for the spa. It’s usually only on the fall when temps are in the 40s or 50s. Like others above indicated, the spa heats quickly with gas. I seem to recall that heat pumps are not good at temps below 50, so we ruled those out. Technology may have changed in 13 years.

We’re never heated the entire pool, as our pool is surrounded by large trees and I have to cover it each fall. What we DO use every day of the summer is our chiller. If you go the electric route and it includes a chiller option, that may be attractive. Our chiller is basically a swamp cooler, so it’s very different from a heat pump, but if a heat pump functions for both purposes, it may be worth considering.
 

Newdude

Well-known member
Jun 16, 2019
4,441
NY
Hey CG !! Normally I am trying to make someone in Northern Michigan aware of the serious drawbacks of the Heat Pump in cool climates. You are in the happy zone where it will work better for you than most of the country.

it could not be more simple. Heating takes BTUs. 3X the BTUs takes 3X less to heat. So if the gas heater takes about 20 min, the heat pump will take about an hour. You could always get in at 90 degrees and warm up the last 20 minutes with the spa.

I checked your statistical weather average and the heat pump will not work most years between mid Nov and mid March. The gas heater will work virtually all year if you wanted to fire up the spa on a random 60 degree day in Feb.

So the question comes down to the same old debate. How will you wish to use it ? Heating cold water is for the gas heater. Heating already warm (70 and above) water is for the heat pump.
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
19,405
Northern NJ
How will you wish to use it ? Heating cold water is for the gas heater. Heating already warm (70 and above) water is for the heat pump.
Gas heaters can heat water with the same efficiency regardless of the air temperature.

Heat pump BTU rating is based on 80 degree air temperature. BTU output declines by about 30% by 50 F air temperature. And most heat pumps cannot operate below 50F. So heat pump is less effective in colder weather.

If you want all year use of your pool and spa then get the gas heater.