Natural Gas or Heat Pump

[DOMO]

Hi all. New member here, and new pool owner (installed last Fall). We have a 10,000 gallon fiberglass freeform shape pool and are debating between natural gas and heat pump options to heat. The pool will sit in full, all day sun so we don't antipate needing to heat June-August, however, we are looking to extend our season in May (perhaps April?) and September/October. We like about 30 miles north of Boston, MA. I've read many differing opinions on nat gas vs heat pump. A heat pump appears to be 1,500 or more initial cost, and lower operating costs, but we are concerned that it will not be effective enough when we really need it to be (when the ambient temperatures outside are cooler than Summer days). Gas has instant gratification, however, our biggest concern is operating costs. One HP co. ran numbers for us and they estimate between 1,900-2,500 per season (Apr-Oct) using natural gas. Knowing that we wont run the heater Jun-Aug, that would be greatly reduced to ~800-1,000. However, I've read posts on this and other boards where people are claiming that natural gas cost them $150. per day to heat their pools! Thats just not in the cards for us. The units we're lookin at are a 200k BTU Hayward or an Aquacal SQ 110. Oh, and we will be using solar sun rings as our 'blanket'. Many thanks in advance for your help!

 

[Bama Rambler]

Welcome to TFP.

In Mass I wouldn't even consider a heat pump. and 200,000 btu isn't enough either. I'd suggest a 400,000 btu gas heater.

If you have plenty of sun exposed roof area to the south, I'd suggest solar heating to either replace or supplement the gas heater. The beauty of solar is that once it's installed the operational costs are minimal.

 

[DOMO]

Hi. Thanks for the reply. This is what I was concerned with the heat pump (effectiveness in MA during cooler months). Regarding the natural gas unit, I was told by a few local companies that a 200k BTU unit was more than enough for my little pool (only 10,000 gallons), why do you think I need 400k? Good tip on solar, perhaps we could add that at a later date to help augment the system, but we need to put on a new roof next yr so thats out for now, and wouldnt solar be fairly uneffective as well in April/May and Sept/Oct in New England? Thanks.

 

[JasonLion]

One of the big considerations is continuous heat all the time vs "event" heating. If you keep the pool hot all the time then 200,000 BTU is just fine. But many/most people only heat for the occasional nice weekend in the spring and fall, and then you want the largest heater possible as it will takes many hours, even days, to bring the water up to temperature.

 

[DOMO]

As this is our first yr with the pool, we don't actually know. Our hope is that during June-August, we won't need to run it at all. In Spring/Fall, we would need to heat for the weekend at the very least, with the occasional run for a mid week evening swim. We've been told 200k BTU could heat 10,000 gallons in a few hrs. ??

 

[bk406]

Get a 400k. I have a 400k on a 14,000 gallon pool in Worcester county.
And you wont use near the gas the heat pump peole said you will. Their trying to cook the books to get to to buy a HP. They are figuring that on continuous use.
FWIW, I hava heat pump too. Its junk in April, most of May, and September on. Works fine June-August. I only have propane so I have the HP to use in the summer to keep the chill off. If i had NG on the property, I wouldnt have the HP. NG is cheap.

 

[JasonLion]

Under ideal conditions a 200k BTU heater can raise the temperature of a 10,000 gallon pool by about 2 degrees per hour. As the water temperature warms up that rate slows down since the pool starts losing more and more heat to the environment. If you were trying to raise the water temperature 15 degrees, it could easily take 10 hours. A 400k BTU heater will do the same job in half the time, 5 hours for this example. That could easily make the difference between swimming the same day you turn on the heater and having to wait until the next day.

 

[UnderWaterVanya]

Be sure to get a solar cover too or something even more insulating. The "solar" part isn't going to heat things much but the lack of evaporation is going to help a LOT.

 

[DOMO]

Hi. We opted for solar sun rings due to the very free form shape of the pool. They don't give 100% coverage, but they fit nicely into the various curves and provide a lot of coverage (more than w/ a straight edged pool).

 

[DOMO]

Hi BK406, Somehow I missed your post earlier, thanks for the reply. I'll look into the initial cost difference between 400k and 200k BTU. The folks at Hayward think 200 is plenty for 10000 gallons. Had a feeling that an HP in our area would be fairly inefficient in the Spring/Fall. Appreciate the help from everyone today, leaning towards NG. Thanks!

 

[dmanb2b]

Get the 400K BTU...cost difference is only maybe few hundred $, but also check to make sure you have adequate NG supply to house that can support a 400k unit first. Being able to heat your pool in half the time is a HUGE plus. Yes a 200K heater is adequate, but a 400K unit would be better. NG usage is about the same as in theory while the unit burns more gas per hour, it will operate much less than a 200K unit.

 

[DOMO]

OK, I'll ask my pool co. on prices. Thanks again!

 

[mpkelley20]

I live about 30 miles south of Boston and just had my pool installed last fall. Its about 25,000 gallons and we went with a 400K BTU heater. Keep in mind that depending on where your gas lines are, it is VERY expensive to run lines in MA. I got 6 quotes from various companies and got ranges from $2,000 to $6,000 to run a line about 75' to 100'. I ended up going with a local gas compnay one town over that was on the low end of the ranges.

Also, my house gas meter was only rated for 375K BTU since my house only uses 200K (at least that's what was described to me). So the gas company (Columbia) came out to upgrade my meter to a bigger one capable of 650K. Any bigger and I was approaching commercial size.

The entire process for permits, installing lines, new meters and then hookup was a long time. Took a few weeks.

of course, gas heaters are really our only option in MA. Heat pumps are totally useless and solar only works if you have ideal conditions which seems to be near impossible to have around these parts.

I do agree with others here on going with the bigger heater. It will heat your pool much quicker and the only minor issue you may to deal with is getting a new meter. And that installation is free from the gas company.

One more thing, the gas company that did my lines also supplies a lot of local homes with propane. I asked about that as an option wondering how much people use and they told me ON AVERAGE, people in the area have one 100 gallon propane tank that lasts the season. Not running constantly, obviously, but for the occasional use like I was planning on doing. At the time, propane was about $3.50 a gallon so I was looking at $350 a year if I fell within the "average". The cost of natural gas was much lower (I don't remember the numbers as it was done for me) but the cost savings would still take many many years to offset the cost of installing the gas lines. But I opted for the gas lines more for convienence and aestetics. Don't want to rely on deliveries and don't want an eye sore of a tank near my pool!

Good luck with heater. I can't wait for the nice weather to get here. I still have my entire patio to do and landscaping. Plus, I still haven't been swimming in my pool yet!!

 

[UnderWaterVanya]

1 gallon of LP is only about 91K BTU - so a 400K BTU heater would use 4 gallons per hour unless I'm mistaken. A 100 gallon tank was considered too small to use for my house for a hot water heater; minimum size recommended was 500 gallon for that - 1500 gallon if furnace was added. My point is that I find it hard to buy that a pool in MA could use only 100 gallons of LP in an entire season.

 

[mpkelley20]

1 gallon of LP is only about 91K BTU - so a 400K BTU heater would use 4 gallons per hour unless I'm mistaken. A 100 gallon tank was considered too small to use for my house for a hot water heater; minimum size recommended was 500 gallon for that - 1500 gallon if furnace was added. My point is that I find it hard to buy that a pool in MA could use only 100 gallons of LP in an entire season.

Possibly true but I was going on what the propane company told me. As I stated, they gave me "average" but didn;t say what that actually was. I originally contacted them after I learned how expensive it was to run a NG line and decided to just do LP. I asked how many tanks I would need and they told me the average customer had 1 and filled it only once a season. So either these people only use it very seldomly or 1 gallon of LP generates more BTU here in MA After these discussions, I changed my mind again and did the NG line.

Whatever the case, NG is the better choice in MA assuming you have gas lines you can extend. We still have tons of people on oil heat in these parts so NG lines are not even an option for a pool heater.

 

[mpkelley20]

Ok...tried to do some math for the OP on cost of running a NG heater.

Hopefully someone will correct me if I am wrong in my numbers

NG is measured in Therms. 1 Therm is equal to 100 cubic feet which equals 100,000 BTU

In MA, if you have Columbia Gas like me, the average rate per Therm is currently $0.35. Yes, that's 35 cents. So you need 4 therms per hour to run a 400K BTU heater which means the cost per hour is $1.40. Using UnderWaterVanya's LP numbers, that cost to run propane would be around $14 an hour.

So if you do NG and run it for 24 hours straight, you are spending about $33.60 in total cost. The $150 number you are seeing must be based on propane cost (and at a lower price that what we have in MA)

 

[DOMO]

mpkelly20, thanks for the add'l posts/info. talked to our pool co. today, they are following up w/ the manufacturer (hayward) re: operating and efficiency costs with bigger than a 200k unit. we will need to upgrade our meter at the house, but as you mentioned, that's a free upgrade from the gas co. estimates for the gas work are ranging from 1,300-2k, higher than we expected, but not terrible. we hear ya on not being able to wait until the warmer weather, we did our installation (a complete nightmare!) in late Aug/Sept. and never got to use it either (although that was a condition of the install and the installer promised us we'd "be swimming by Labor Day weekend"... yeah right!). needless to say, they're not installing our heater! thanks again for the help.

 

[bk406]

1 gallon of LP is only about 91K BTU - so a 400K BTU heater would use 4 gallons per hour unless I'm mistaken. A 100 gallon tank was considered too small to use for my house for a hot water heater; minimum size recommended was 500 gallon for that - 1500 gallon if furnace was added. My point is that I find it hard to buy that a pool in MA could use only 100 gallons of LP in an entire season.

You're right, thats too low. I have two, 150 gallon tanks. I spot heat in the spring and fall, and even sometimes in the summer if its a little raw and wet (like we get in early June). I usually end up using about 400 gallons a season. I pay $2.50 a gallon, so thats about $1000 per year to heat the pool. I have a 400k hayward.

If I had NG, I'd scrap the heat pump. It does work well in the summer. We like 85 degree water, so a heat pump has a tough time anyway.
NStar says they might run gas in oru neighborhood, but im not holding my breath on it.

In MA, if you have Columbia Gas like me, the average rate per Therm is currently $0.35. Yes, that's 35 cents.

You also have to figure the taxes, delivery charges, etc in the cost. Once thats factored in, it run around $0.75 +/-. Still cheap as heck. I figure with having to run a heat pump for 15 hours a day in some cases up here just to maintain 82 degree water (my experience) there is no cost savings at all. You spend more money in electricity than on NG. NG heater up here is a no brainer if you have the gas in your neighborhood.

 

[UnderWaterVanya]

Gas lines in my neighborhood stop 4 houses from me. I have a heat pump. My father-in-law (where the pool is) has gas but I'm not sure I can talk them into adding a heater.

 

[Azmp1]

Useful info folks, as this is what i'm trying to figure out as well... NG or propane. i do have NG in my house, but told will need to upgrade the meter and will need to go to bigger line going to the house, so i'm looking at several thousand $$ to get this done... now, spoke with propane dealer today, he recommends 2x100g tanks if go propane, installation is $1200 including the first fill for both tanks, not too bad. The propane price here in Baltimore area is $2.65/gl vs NG at $.65/therm, so definitely cheaper to go with the NG from operating cost perspective except the initial cost and that initial cost is what's killing me....

In any case, heater isn't being done this year anyway as we're doing an auto cover and i want to see how much that will help with keeping the water warmer for the first summer, what i'm struggling with is should i do the prep for NG now (will be cheaper since most of the trenching is there for electrical), or just say screw it, don't do anything this year, see how auto cover works and if still needed add propane heater later. Oh decisions, decisions... ))