Propane heaters

[tcat]

How fast does a propane heater warm a 15k gallon pool compared to solar? I know a lot depends on heater or panel size, assume sized nominally. Just wondering if I can get by without a cover. Say heat from 8 am to noon and swim in the afternoon 2 or 3 times a week.

I'm actually considering replacing a dual fuel a/c with a heat pump because of high the of propane to heat the house. Don't want to make the mistake of buying a propane heater just to regret it 1 year later. House has a 3/4" propane line at the pump area. Pool 50% shade.

 

[jblizzle]

Those are not really comparable.
Solar is going to add heat slowly over several days and with no cover, you may lose all the heat to evaporation overnight.
Propane/gas heaters add heat much more quickly, although again you will lose heat to evaporation.

For example, a panel solar panel setup may be able to add around 700,000 BTUs to the water per day (assuming bright sun).
A large gas heater can add that in 2 hours, regardless of the weather.

For your pool, 15k gallons = 124500 pounds of water. For a 10 deg F rise, you will need 1,245,000 BTUs. So a large 400k BTU gas heater running at 85% efficiency can add 340k BTU per hour. So it would take 3.7 hours to add 10 degrees ... neglecting losses of heat to the environment. Assume ideal weather (and no losses over night), it may take the solar 2 days to add 10 degrees.

FYI, my solar in the spring/fall can add 5-6 degrees in the day, but with no cover, I lose around 5 degrees overnight.

 

[tcat]

Thanks! So if you swim from 6-8pm either will probably do the job without a cover. Trying to avoid a cover since the pool is kidney shaped with 1/3 of it with a 2' raised deck. I have a bubble cover, used it once since it was such a pain.

 

[jblizzle]

Well, that is not the conclusion I was trying to make. Depending on your air and water temp and expectation when you are looking to swim ... I don't think the solar is going to add enough heat ...

I agree that covers are a pain which is why I do not have one, but they are crucial to maintaining the heat at night.

 

[tcat]

OK. Propane looks most suited for my need. Mainly looking for +5 degrees within 3-4 hours of when needed. Pool stays between 83 and 85 all summer, 83 now. Wife likes 86+ and it never hits it. Just don't want to fill my 500 gallon tank more than once a year.

 

[jblizzle]

Well if you are talking about adding a few degrees ONLY in the summer, then solar would be fine and should help. But it will not have the ability to add a lot of heat once the weather cools off. You just need realistic expectations.

 

[SunnyOptimism]

One other consideration for propane and NatGas heaters is the source. You said you have 3/4" lines in the house? For NatGas (low pressure, high volume), I had to have a 2" line run from my gas main to the heater and then it was necked down to 3/4" right at the equipment pad. There is NO WAY I could have fed my gas heater using a 3/4" line that was external to my house and nearer to the equipment pad. Also, a pool heater is going to consume A LOT of gas to heat a 15k gallon pool. You need to consider if your propane tank is capable of supplying the volume of gas needed.

Question - just for clarification, you have a propane tank on your property or do you have natural gas supplied by your municipality?

 

[tcat]

One other consideration for propane and NatGas heaters is the source. You said you have 3/4" lines in the house? For NatGas (low pressure, high volume), I had to have a 2" line run from my gas main to the heater and then it was necked down to 3/4" right at the equipment pad. There is NO WAY I could have fed my gas heater using a 3/4" line that was external to my house and nearer to the equipment pad. Also, a pool heater is going to consume A LOT of gas to heat a 15k gallon pool. You need to consider if your propane tank is capable of supplying the volume of gas needed.

Question - just for clarification, you have a propane tank on your property or do you have natural gas supplied by your municipality?

Propane tank in yard (only one on the block), so choose provider. Go through about 400 gallons per year (heat, water, stove top), around $2.50/g but haven't filled it in about a year, so probably higher cost now. 50% of pool sees sun from noon to 5 (lots of shade), but I have lots of SW area for panels. Solar is looking a lot more wallet friendly! It will get the few degrees my wife needs/wants, and maybe extend the season a week or two.

 

[SunnyOptimism]

Propane tank in yard (only one on the block), so choose provider. Go through about 400 gallons per year (heat, water, stove top), around $2.50/g but haven't filled it in about a year, so probably higher cost now. 50% of pool sees sun from noon to 5 (lots of shade), but I have lots of SW area for panels. Solar is looking a lot more wallet friendly! It will get the few degrees my wife needs/wants, and maybe extend the season a week or two.

Yup, and solar is free! As @jblizzle said, if all you need is a few degrees, a solar heater and a solar pool cover will get you what you need. 15k gallons of water is a lot of water to heat up and, without any pool cover, it will all be wasted heat.

I have a 16k gal pool and a ~1000 gal attached spa and I only use the gas heater on the spa. I'm sure SouthWest Gas would love for me to heat the pool up but I'm not about to line their pockets any further with my hard earned $$$$


Sent from my iPhone using Tapatalk

 

[mgarf33]

How much is electricity?
A heat pump is likely the most economical for you.
For 1 million btus output of an 80% propane furnace at $2.90 a gallon, propane would cost you ~$39-$40
For 1 million btus output of a heat pump with an electric rate of 12¢/kW it would cost you ~$5-$6 in warm weather operating at 6.0 COP and $17-$18 in cold weather operating at 2.0 COP.
Heat pumps will take longer to heat, but cost less to operate.

 

[tcat]

Even without the cover, free solar heat isn't really wasted. If I only need 4-5 degrees in 90 degree sunny weather, I'm sure I'll get 4-5 during the day to enjoy before dark. Then just start over next day. May try solar since it's lowest cost and there's plenty of sun here.

 

[one_knight4u]

What about looking at setting up a moderate sized heater along with 80-120 sq ft of solar. Basically the solar will be comprised of 2-3 40 ft panels. Each panel costs around $100. After the initial cost, its pretty hard to beat free heat, and being in central Texas, there is alot of sunshine in the summer. You might find out that the best bang for your buck will be in solar. The system can be expanded quite easily by adding more panels.