Electric spa heater replacement

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J

jb

0
Jul 2, 2011
103
North Texas
Hello,

I need to replace an old electric spa heater to an inground pool. The old model is a teledyne TE-115 220 volt 11.5 KW heater. It basically sucks , but there is no natural gas in the neighborhood and I'm not going to do a propane tank. So it is electric. Any recommendations? Obviously, I'd like to buy the same so that there was no plumbing changes but it appears TE-115 is NLA. Any suggestions welcome!
 
Are you heating a spa or a pool (or both)? I don't think electric can handle a spa. I think the best you can get is 150k btu and that is on a really good ideal day. They also cost upwards of $5k.
 
JamesW said:
Have you considered a heat pump?
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Do you have one? Not heard of them for spa heating but interested if there are better options for sure!

PoolGate said:
Are you heating a spa or a pool (or both)? I don't think electric can handle a spa. I think the best you can get is 150k btu and that is on a really good ideal day. They also cost upwards of $5k.
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Heating the spa. I think you maybe miswrote when you wrote can't heat a spa? I think you meant pool? In which case you are right - it would never heat the pool. THe 11.5kw heater would heat the spa only up at a rate of 10 degrees per hour. In the warmer months thats not a hassle and it heats up in an hour or two. In winter it can be an all day event so not really worth it.
 
jb said:
Do you have one? Not heard of them for spa heating but interested if there are better options for sure!



Heating the spa. I think you maybe miswrote when you wrote can't heat a spa? I think you meant pool? In which case you are right - it would never heat the pool. THe 11.5kw heater would heat the spa only up at a rate of 10 degrees per hour. In the warmer months thats not a hassle and it heats up in an hour or two. In winter it can be an all day event so not really worth it.
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I meant heatpumps. For regular heaters the only brand I haves seen is "Coates".
 
Well by the numbers a 11.5 kW resistance heater will output roughly 40 kBTU. It will do that day or night rain or shine until it fails.


A 100-140 kBTU heat pump will use the same amount of electricity and roughly triple the heat put into your spa on warm weather days. Warm weather being outside air temps above 60F. On colder days 45-60F you will at worst still get the 40kBTU your electric heater is now producing. So on its worst days a large heat pump will make as much heat as you have now and on its best days will be at least 3x more efficient on energy usage than what you have now. Also a heater that size will be big enough to warm your whole pool.

As for costs to buy and install you already have an electrical circuit big enough to power a heat pump so there is minimal costs there.

The heat pump itself will cost about 3-4k depending on how big you go.

There will be some plumbing to redo as well.
 
CJadamec said:
Well by the numbers a 11.5 kW resistance heater will output roughly 40 kBTU. It will do that day or night rain or shine until it fails.


A 100-140 kBTU heat pump will use the same amount of electricity and roughly triple the heat put into your spa on warm weather days. Warm weather being outside air temps above 60F. On colder days 45-60F you will at worst still get the 40kBTU your electric heater is now producing. So on its worst days a large heat pump will make as much heat as you have now and on its best days will be at least 3x more efficient on energy usage than what you have now. Also a heater that size will be big enough to warm your whole pool.

As for costs to buy and install you already have an electrical circuit big enough to power a heat pump so there is minimal costs there.

The heat pump itself will cost about 3-4k depending on how big you go.

There will be some plumbing to redo as well.
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I just don't think this is true based on my research and anecdotal evidence from people I know that have heat pumps including on this forum. General consensus is that you get 1-2 degrees per day with a heat pump. His heater he says is putting out 10 degrees per hour (albeit in that small spa). My PB also told me there is no way a heat pump will work on a spa as it just won't get the water warm enough. My own experience with a heat pump shows they are good for maintaining temp but not much else. I think you'd get almost the same temperature increase using a solar cover. Certainly they do almost nothing in the shoulder months when you want a heater most. My gas heater has a 10 degree rise coming out of the heater returns. I can't even feel a temp difference on my neighbors heat pump.

If he is insisting on electric I think his only option is a resistance style heater like he already has.
 
It is a rental house so I am not into spending 3-4k on a heatpump. I would be open to a smaller gas heater, I'm not 'insisting' on electric per se, but there is no natural gas in the neighborhood - it is electric only. I'd really like to find a plug and play solution. The Hayward electric heater for around $600 looks almost exactly the same dimensions as the teledyne I currently have.
 
PoolGate said:
I just don't think this is true based on my research and anecdotal evidence from people I know that have heat pumps including on this forum. General consensus is that you get 1-2 degrees per day with a heat pump. His heater he says is putting out 10 degrees per hour (albeit in that small spa). My PB also told me there is no way a heat pump will work on a spa as it just won't get the water warm enough. My own experience with a heat pump shows they are good for maintaining temp but not much else. I think you'd get almost the same temperature increase using a solar cover. Certainly they do almost nothing in the shoulder months when you want a heater most. My gas heater has a 10 degree rise coming out of the heater returns. I can't even feel a temp difference on my neighbors heat pump.

If he is insisting on electric I think his only option is a resistance style heater like he already has.
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BTU values are pretty cut and dry when it comes to heating water. 1 BTU will heat 1 pound of water 1 degree. It doesn't mater how the BTU's are generated or the fuel source they are coming from.

Heaters are rated in BTU/hr so as to make them directly comparable to each other. There is 0 reason why a heat pump capable of generating 140k BTU/hr wouldn't be able to heat a spa up to temperature when the original heater was only capable of 40k BTU/hr. Even on its worst day that heat pump will be able to put out at least 40k BTU. That is not anecdotal nor is it speculation. Its thermodynamics.

The upfront cost on the equipment is obviously a different story. As jb has pointed out a replacement electric heater is considerably cheaper than a heat pump.
 

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CJadamec said:
BTU values are pretty cut and dry when it comes to heating water. 1 BTU will heat 1 pound of water 1 degree. It doesn't mater how the BTU's are generated or the fuel source they are coming from.

Heaters are rated in BTU/hr so as to make them directly comparable to each other. There is 0 reason why a heat pump capable of generating 140k BTU/hr wouldn't be able to heat a spa up to temperature when the original heater was only capable of 40k BTU/hr. Even on its worst day that heat pump will be able to put out at least 40k BTU. That is not anecdotal nor is it speculation. Its thermodynamics.

The upfront cost on the equipment is obviously a different story. As jb has pointed out a replacement electric heater is considerably cheaper than a heat pump.
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Interesting and beyond my knowledge of thermodynamics! But the real question is does anyone use a heatpump to heat a hot-tub? I have not seen anyone that does and was specifically told it just won't work. My PB said NG or Propane is all they offer for hot-tub heating.
 
It really depends on the specifics of the installation if a heat pump will suit your needs, but every heat pump manual I've read has a description of a pool mode and a spa mode. I looked into a lot of heat pumps before buying one.

My own heat pump could easily heat a stand alone hot tub up to about 500 gallons capacity. If it was an in ground or spill over spa there would be too much heat loss for something as small as my heat pump, only 75k BTU, to keep up.

You are missing out on a lot of products by only considering what your PB recommends.

And yes there are those out there who use heat pumps for spas.
 
I've never looked into heat pumps but in principle their output is highly dependent on air temperature (low is bad), relative humidty (low is bad), AND water temperature (high is bad). Spas are the worst combination of all three since they are used on cool days with high water temperatures. I can see that a lot of them just wouldn't have the output to work well for a spa.

Do any of them show their output at 104° F with cool air temps and low relative humidty?
 
The issue I'm concerned about is how well would a heat pump work out in the desert where I'm at with 5-10% RH conditions. I don't think a heat pump will work the more I read about it. Solar heating makes sense, but I don't know to maintain the spa's temperature into the night.
 
jb, You say it's a rental so I am guessing you are the owner. Put the propane in and make the renters pay for it. I am sure you can increase the rent a little bit to cover you portion of the cost. If they want to use it, they have to pay for the propane. People do this all the time here in Florida and I am sure else where.

I would also look at replacing the homes hot water heater and use a on-demand propane unit. It'll save you some money and you have two things on gas so it's even easier to get the rent up.

The most efficient and quickest way to heat is with gas.
 
bizzle said:
The issue I'm concerned about is how well would a heat pump work out in the desert where I'm at with 5-10% RH conditions. I don't think a heat pump will work the more I read about it. Solar heating makes sense, but I don't know to maintain the spa's temperature into the night.
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Solar panels won't produce any heat at night or if the temps are cool outside. In fact, if you run the solar panels when it's cool out, you will cool the pool off. Both solar and heat pumps rely on the outside temps to be warmer to create heat. With a spa, I would always go with gas.
 

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