Heater Options

[brightblonde]

We are currently testing 2 solar heaters & using a blue solar cover. But it may not be effective here. August has been cool & cloudy & wet. I want to enjoy the few sunny days we get.

What is involved with installing natural gas, propane or electric heat? Do I contact a pool contractor, plumber or electrician?

 

[CraigMW]

Well, it highly depends on a) what you are seeking and b) what services you have. For a standard petroleum based heater, your choices are NG and propane. If you have NG service at your home, then you would pick this. The choice between electric and the other two would be if you would want a heat pump vs. standard heater. A heat pump has the advantage of being able to cool the water in places where the water gets too hot (never the case for our pool in coastal Southern California). Some have argued this from an efficiency standpoint, but I really don't get the argument. It just doesn't work here in California, where electricity gets upwards of $0.34/kWh in the higher tiers. In addition, heat pumps are not very good for rapid pool heating, whereas a 400K BTU heater can get the job done reasonably quickly. Also, if you have an attached spa, it's possible to keep that running far past the pool season with a gas heater. Lastly, an electric heat pump typically is considerably more expensive than a gas heater. All in all, it really depends on balancing the cost to operate, the ability to run that service to your equipment pad, and the kind of climate you have. I'd think a gas heater would make the most sense, given your description.

 

[brightblonde]

Hi Craig. Thanks for your reply. We have NG service here. But it's mostly concrete between the house & pool. There is only a narrow path of grass that was recently dug for the electric line & pump outlet. No spa.

 

[Poolsean]

Gas - Quick heat due to higher BTU output of gas heaters. Great for spot heating. Works better when tempertures are continually below 50 degrees. If you don't have a gas line readily available or accessible, it can be costly to have the lines run to where the heater would be. Gas heater issues include multiple components internally that can fail, gas orifaces clogging up, and heat exchanger damage (due to water chemistry imbalance). Gas heaters are usually cheaper up front. But if you desire to keep your pool heated to a certain temperature, it can get costly.
Heat Pump - Great for maintaining temperatures throughout the normal pool season. Most heat pumps will operated efficiently down to about 55 degrees. Some units will start shutting down around 50 - 55 degrees ambient air temperatures. Some will operate down to the mid 40's. The HEAT AND COOL feature not only will allow you to cool your pool if it gets too hot during the summer (which makes the water more comfortable for most, and reduces chemical costs by the excessive heat not burning up the chlorine), but also allows the Heat Pump to operate lower than the 55 degree cut off of some systems. The Heat and Cool feature allows the freon to reverse directions for a brief period of time, melting any frost or ice that will build up around the heat pump. Once defrosted, it will revert back to the heating mode to add "some" heat to your pool/spa. Heat Pumps need to be mounted outside with 2' of space around it, and 5' of space above it. Heat Pumps are more expensive up front, but costs much less to maintain a pool at temperature throughout your swim season. Heat Pumps will also require more Electricity (typically 30 - 60 amps, 220 VAC), which your electrical panel may or may not have available. Heat Pumps do not do a good job at spot heating a pool, but shouldn't be a problem for spas. Heat Pumps usually are made with Titanium Heat Exchangers so there's little damage from pool water chemistry. There are fewer components that can fail internally.
For NJ, heat pumps will work very well to maintain temperatures.

Both types are prone to rodents chewing on wires. Both will increase your cost of operation to get your pool heated. In BOTH cases, you should continue to use your solar blanket to retain any heat added to your pool from evaporative heat losses.

 

[CraigMW]

Gas - Quick heat due to higher BTU output of gas heaters. Great for spot heating. Works better when tempertures are continually below 50 degrees. If you don't have a gas line readily available or accessible, it can be costly to have the lines run to where the heater would be. Gas heater issues include multiple components internally that can fail, gas orifaces clogging up, and heat exchanger damage (due to water chemistry imbalance). Gas heaters are usually cheaper up front. But if you desire to keep your pool heated to a certain temperature, it can get costly.
Heat Pump - Great for maintaining temperatures throughout the normal pool season. Most heat pumps will operated efficiently down to about 55 degrees. Some units will start shutting down around 50 - 55 degrees ambient air temperatures. Some will operate down to the mid 40's. The HEAT AND COOL feature not only will allow you to cool your pool if it gets too hot during the summer (which makes the water more comfortable for most, and reduces chemical costs by the excessive heat not burning up the chlorine), but also allows the Heat Pump to operate lower than the 55 degree cut off of some systems. The Heat and Cool feature allows the freon to reverse directions for a brief period of time, melting any frost or ice that will build up around the heat pump. Once defrosted, it will revert back to the heating mode to add "some" heat to your pool/spa. Heat Pumps need to be mounted outside with 2' of space around it, and 5' of space above it. Heat Pumps are more expensive up front, but costs much less to maintain a pool at temperature throughout your swim season. Heat Pumps will also require more Electricity (typically 30 - 60 amps, 220 VAC), which your electrical panel may or may not have available. Heat Pumps do not do a good job at spot heating a pool, but shouldn't be a problem for spas. Heat Pumps usually are made with Titanium Heat Exchangers so there's little damage from pool water chemistry. There are fewer components that can fail internally.
For NJ, heat pumps will work very well to maintain temperatures.

Both types are prone to rodents chewing on wires. Both will increase your cost of operation to get your pool heated. In BOTH cases, you should continue to use your solar blanket to retain any heat added to your pool from evaporative heat losses.

Sean:

This is one thing I don't understand about heat pumps. I get the idea that they simply move heat from one place to another, in exactly the same fashion as an air conditioner. So, it is not a matter of generating heat, just redirecting it. What I don't get is how it could make sense from an energy efficiency standpoint. To keep our pool heated here in coastal SoCal during the summer without a pool cover, we spent about $185 on natural gas. During the same period, if a heat pump were on for the same amount of time as my heater, it would approximate to our usage of A/C and be several times that cost in electricity. Given that a heat pump takes longer to heat a pool than a NG heater, wouldn't that mean that the heat pump was on much more frequently? And pulling upwards of 40A at 220V would be 8.8 kW, so over a 24h period of heating the pool, this would amount to 211 kWh. At a top tier cost from SoCalEdison of $0.35, this works out to $73.92 to heat up the pool over that 24h. Add that up over a month and I don't see how this helps. Of course, one could always get a pool cover to reduce heat loss via evaporation, but that's the same issue with a NG or LP heater. What am I missing in this equation?

Craig

 

[brightblonde]

Sean, thanks for your info.

Our pool temp has been 79-80 all month. A bit cool. We spent most time on the floatie instead of in the water.

My goal is 84. And 1 hr of swim time per day. Also hoping to extend it thru Sept, if possible.

 

[dmanb2b]

Keeping the water at 84 through these cool nights is going to be expensive, but if you have room for one more panel, probably your most cost effective option. Our 24 ft is in the 78-80 deg range right now, running 2 4x20 panels and religiously covering the pool with the solar cover at dusk and it does not get uncovered until temps come up around noon or so. Also make sure not to run your pump when there is no sun on the panels, that will actually cool the pool.

 

[Poolsean]

HI Craig,

Are you running your heater every day? The difference is that if you're spot heating your pool with the gas heater, it makes a difference in what your operating cost would be vs maintaining temperatures every day.
The 40 amp breaker is not necessarily the amp draw. The KW draw calculated by (BTU output/3412 BTU per KW)/COP = KW Input. The heat pump will seldom run 24/7, but for calculating a worst case scenario, I guess you can use that number, but to be fair, you would also need to calculate the gas heater cost, based on 24/7 also.
While I agree that a heat pump is not always the right fit for every pool application, a very high % of applications will result in considerable cost savings over a gas heater (in the right application).
Uncovered pools in windy conditions, high electrical costs, continual cold temperature operation, and intermittent spot heating are typically not the right fit... $0.35 is a high electrical cost for sure!

 

[CraigMW]

Sean:

Yeah, that's running the heater whenever the pump is on, so not quite 24/7, but enough to keep the water at 85F each day without a pool cover. In our case, the pool "wants" to be at around 78F, as this is where it settles when I turn off the heater, despite the air being quite a bit warmer. But, the heater heats the pool rather quickly, so it doesn't need to be on 24/7. It's a bit scary when it is on though, as the gas meter makes a significant sound of gas flow and the meter spins quite rapidly!

 

[ps0303]

Gas - Quick heat due to higher BTU output of gas heaters. Great for spot heating. Works better when tempertures are continually below 50 degrees. If you don't have a gas line readily available or accessible, it can be costly to have the lines run to where the heater would be. Gas heater issues include multiple components internally that can fail, gas orifaces clogging up, and heat exchanger damage (due to water chemistry imbalance). Gas heaters are usually cheaper up front. But if you desire to keep your pool heated to a certain temperature, it can get costly.
Heat Pump - Great for maintaining temperatures throughout the normal pool season. Most heat pumps will operated efficiently down to about 55 degrees. Some units will start shutting down around 50 - 55 degrees ambient air temperatures. Some will operate down to the mid 40's. The HEAT AND COOL feature not only will allow you to cool your pool if it gets too hot during the summer (which makes the water more comfortable for most, and reduces chemical costs by the excessive heat not burning up the chlorine), but also allows the Heat Pump to operate lower than the 55 degree cut off of some systems. The Heat and Cool feature allows the freon to reverse directions for a brief period of time, melting any frost or ice that will build up around the heat pump. Once defrosted, it will revert back to the heating mode to add "some" heat to your pool/spa. Heat Pumps need to be mounted outside with 2' of space around it, and 5' of space above it. Heat Pumps are more expensive up front, but costs much less to maintain a pool at temperature throughout your swim season. Heat Pumps will also require more Electricity (typically 30 - 60 amps, 220 VAC), which your electrical panel may or may not have available. Heat Pumps do not do a good job at spot heating a pool, but shouldn't be a problem for spas. Heat Pumps usually are made with Titanium Heat Exchangers so there's little damage from pool water chemistry. There are fewer components that can fail internally.
For NJ, heat pumps will work very well to maintain temperatures.

Both types are prone to rodents chewing on wires. Both will increase your cost of operation to get your pool heated. In BOTH cases, you should continue to use your solar blanket to retain any heat added to your pool from evaporative heat losses.

I love it when a consumer is sold a heat pump to heat a spa. They call me to swap it out to a gas fired heater because they can't get the spa warm enough during the cooler months. I always tell a customer that if you just have a pool, go heat pump or solar, solar being the better option seeing it pays you back sooner. If you have a spa, you need gas or if you want to heat the pool for company that comes around the winter holidays.

 

[Poolsean]

A BTU is a BTU, no matter where it comes from. If a gas heater is burning 400,000 BTUs, at 75% efficiency, it's only putting 300,000 BTUs of heat. If a heat pump is putting in 130,000 BTU's, that's about 43% the output of the gas heater. Therefore, if a spa heats up in 15 minutes, it will take about 35 minutes with a heat pump. Not really that much of a difference.
NOW, if there is a blower on a spa, the blower will just be sucking in cold air a cooling the spa off, quickly. In this condition, or just plain cold winter temperatures, the more BTU's you have, the less the heat loss will affect spa water temperatures.
Not that it won't work, but as I said, there are limitations to proper and efficient heating of a pool or spa.

 

[dmanb2b]

A BTU is a BTU, no matter where it comes from. If a gas heater is burning 400,000 BTUs, at 75% efficiency, it's only putting 300,000 BTUs of heat. If a heat pump is putting in 130,000 BTU's, that's about 43% the output of the gas heater. Therefore, if a spa heats up in 15 minutes, it will take about 35 minutes with a heat pump. Not really that much of a difference.
NOW, if there is a blower on a spa, the blower will just be sucking in cold air a cooling the spa off, quickly. In this condition, or just plain cold winter temperatures, the more BTU's you have, the less the heat loss will affect spa water temperatures.
Not that it won't work, but as I said, there are limitations to proper and efficient heating of a pool or spa.

Certainly agree that a BTU is a BTU and your calc is about right, but I think that assumes no heat loss. I'm sure this is closer to being accurate in our southern states, but up north is just takes too long for a HP to heat a spa on demand.

Anyhow...back to the OP's question, this seems like a fairly small pool, so not sure if we even need to discuss a 400K BTU NG heater. Either additional panels, HP or NG/LP heater will work.

 

[brightblonde]

dmanb2b,

Yes, it's fairly small ... 18x52. I appreciate your suggestions. Particularly, when to use the solar cover & run the pump.

I like reading all the replies and learning.

 

[ps0303]

You really have to consider if you want it heated up sooner rather then later. Sooner, gas is the answer. The addition of the gas along with the solar would be a great mix.

 

[brightblonde]

The addition of the gas along with the solar would be a great mix.

That sounds really good. Thanks!

We are considering a semi-inground next summer. Similar size. But are they typically cooler?

 

[bwnet2k]

I've had my new pool now for just over a year and decided to install a natural gas heater in the spring. After researching heaters online, I was surprised to find the efficiency ratings are only in the 80%-82% range, and found a couple units that were more efficient but they were for commercial sized pools. Are there any residential (400k BTU) units that are more efficient to use for my hard earned dollar?

 

[danpik]

The big issue with higher efficiencies is the way they are produced. Anything higher that 85% starts to get into what is refered to as a condensing furnace. This means that the exaust gas is too cold to contain the moisture in it which then condenses out inside the exaust and heat exchanger areas. This condensate is extreemly acidic. In forced air furnaces, this problem was fairly easy to overcome and is why there has been dependable forced air furnaces on the market since the early 90's or late 80's. High efficient boilers on the other hand had all sorts of problems back then to the point that all manufacturers abbandoned them untill recently. New, high efficient boilers are an entirely different breed from their predacessors. They are commonly refered to as modulating boilers now. This means that the flame intensity modulates from 100% down to as low as 15% depending on how hot the return water is in the system. In order for these to work this way there has to be what is called a boiler loop in the plumbing. This loop modulates water flow from the output side directly back into the input side to keep the boiler temp constant. This constant or near equal boiler water temp is critical to keep the heat exchanger from cracking from thermal shock as these are made from aluminum, magnesium or some other exotic alloy. To use one of these in a pool setting would not get much eficiency as the water temp coming back from the pool would always be too cool to allow the modulation to go below 100%. Also air bubbles are not good in these systems as they can cause hot spots. As with any new technology there also comes the learning curve and the maintenance that goes with it. another big factor is the cost. Currently I have in my house a 85% efficient 100,000 BTU Lenox boiler. I also have a 100,000 BTU Hayward heater on my pool. My pool heater, which by the way has less controls on it than my house heater (Aquastat, Pump, Etc) cost almost twice what my house boiler cost. I just installed a Weil McClain ultra 90 93% efficient boiler for a customer. The boiler and associated parts to install it were $4500.00. Does this mean a 93% efficient heater for a pool will cost $9000? I don't know.....

Something else to look at...
I tracked my heater usage a couple years ago to see how much it cost me for the season. I found that I used it for a total of 200 hours (I don't run it all the time) At that time gas cost $.75 CCF (100 CuFt) being there is aproximatly 100,000 BTU in a CCF of gas I determined that I used about 1 CCF for each hour of run time or 200CCF for a cost of $150.00 for the season. If I were to gain the 13% efficiency to get to 93% I would have only saved about $20.00

 

[tcat]

Interesting discussion. I'm in Texas, pool has been 82-84 degrees all summer. Hit 80 yesterday with a cooler weekend. I have Propane with a pipe at the pump. Debating Propane vs Solar. Goal is 84-85 degrees for as long as affordable, December? If pump/solar is run say from 1:00-6:00, and desire to swim is say from 5:00 to 7:00.... what is approx. cost to heat with Propane? Will solar heat to 85 by 6:00, say with no solar cover?

Also, I don't plan on "winterizing" since it seldom freezes (and I have freeze control pump). Is it wise to put a cover on the pool? This is my first house with a pool, and first season. I have a sun-sail covering half the pool and Oak trees covering another 25%. I don't mind scooping leaves. How cold does water really get in the winter (in Texas)? I don't think a solar cover would do much good with sun on less than 50% of the pool 2-3 hours a day.