Heat Pump Vs Solar Heater (northern Ca)

[sjpoolowner]

Hi all,

Glad to find a great forum.

I own a pool in San Francisco bay area and am considering to add a heater. I've done some brief research and still deciding between solar heater and heat pump. Slightly leaning toward to the latter, though.

I like the solar idea for its low operating cost but became a little bit hesitant because

a) I'm not too comfortable about drilling holes through the roof

my equipment site is far from house (like 30 feet away) and I will have to run the pipes across backyard to get the solar heating

c) the area of my south or west facing roof is not really big. The biggest is east side but that is even far from the equiptments.

Heat pump sounds more promising and I have the following questions.

a) will it be suitable for northern CA climate?

what is the typical operating cost per month if I want to set the temp between 80 and 85? The surface area of my pool is about 500 sq ft.

c) where can I find a dealer near my area? I've been only successful finding solar heater dealers.

Or should I still consider solar heating for its operating cost efficiency? Any help would be greatly appreciated. Thanks!

[ps558]

Hi all,

Glad to find a great forum.

I own a pool in San Francisco bay area and am considering to add a heater. I've done some brief research and still deciding between solar heater and heat pump. Slightly leaning toward to the latter, though.

I like the solar idea for its low operating cost but became a little bit hesitant because

a) I'm not too comfortable about drilling holes through the roof

my equipment site is far from house (like 30 feet away) and I will have to run the pipes across backyard to get the solar heating

c) the area of my south or west facing roof is not really big. The biggest is east side but that is even far from the equiptments.

Heat pump sounds more promising and I have the following questions.

a) will it be suitable for northern CA climate?

what is the typical operating cost per month if I want to set the temp between 80 and 85? The surface area of my pool is about 500 sq ft.

c) where can I find a dealer near my area? I've been only successful finding solar heater dealers.

Or should I still consider solar heating for its operating cost efficiency? Any help would be greatly appreciated. Thanks!

If the air temp is above 65 degrees the heat pump will work. heat pumps are made to be set and forget. Any pool place should access to them Pentair, Hayward, Jandy all make them.www.aquacal has tons of info on heat pumps. get one that rated with at least 6 cop more efficentcy. Aquacal also used to have a cost program to see what the cost of operation would be. A Heat pump is like a Central AC unit except is heats instead removing heat

[Pool Clown]

The San Francisco I know has a lot of cloudy days in the Summer. Might be cutting it close to the 65 degree barrier too! A gas heater is "positive heat".

Edit: skipped over the "bay area" part the first time. I can tell you that in the bay area, I see NO heat pumps! sounds crazy but i don't. Gas is cheaper (than elec.) around here, so maybe thats it. See lots of solar tho. Where abouts is the pool?

[sjpoolowner]

Thanks for the replies. I live in San Jose, so we don't really get cloudy days during April - October and temp is well over 65, I think.

Yeah, I don't really get good info about heat pumps in my area. Will the operating cost be really high? I heard I have to pay $$$ for gas heating, but is it actually more expensive to run a heat pump than a gas heater?

[chem geek]

A heat pump is generally less expensive than a gas heater for the same amount of heating BUT it heats much more slowly than a gas heater under the usual conditions when you want such heat such as days that are not sunny. Heat pumps are far better at maintaining a temperature than at rapidly raising it. I also live in the S.F. Bay Area (in San Rafael; Marin County) and have Fafco solar panels for pool heating. This works great in the summer even having our pool at 88F since it is used for therapy exercises (and we both like it warm). Nevertheless, we use some gas assist when needed and this gets expensive in April/May and October/November, though there are a few days sometimes needed in June and August/September. If you don't keep your pool this warm, you probably won't need gas assist except in those outlier months. Note that when making comparisons you should factor in the higher pump electricity costs needed for the flow rates through solar panels (though in practice unless you have a variable speed/flow pump or at least a 2-speed pump, you won't see savings). When I switched to a Pentair IntelliFlo VF pump, I cut my pump electricity costs in half from $1400 to $700 per year.

Take a look at this site. Note that the annual savings chart compared to gas uses electric and gas rates that aren't what we have. In the Bay Area, you will likely be at least at 15 cents per kilowatt-hour and could be at 30+ cents depending on your tier. Likewise, the gas rates are more like $1.70 per Therm. So if you are at a higher tier for electricity rates, then using an 80% efficient gas heater makes the costs roughly the same. Investing in a more efficient 95% gas heater might make more sense. Also note that this comparison uses a COP of 5.0 and that the heat pump efficiency won't be nearly that high in the spring and fall when you need the heating most, assuming you want to extend the season. Also note that for these comparisons they are only heating the pool to around 78-82F.

Note that the best way to save energy costs is by using a pool cover. The savings are HUGE, especially if you keep your pool warmer or heat it in the extended season (spring/fall). An opaque electric pool safety cover roughly cuts the overnight temperature drop in half while a bubble-type better insulating cover cuts the drop to 1/4 so very significant.

[Pool Clown]

Beings i don't see any Heat pumps = i don't know about them. I admit that. 25+ years and not one! Maybe someone can tell me why. This (bay area) seems to be an area that can support them.

If you are in San Jose?, Solar all the way.

+ 1 On the cover too.

[Mark]

I think the reason is electricity costs as Richard pointed out. Most people are in the third tier with a swimming pool so they are now paying $0.40 per kwh so that is likely to be the rate that the heat pump will work on. With COP of 5.0, the cost per 100,000 BTUs is about $2.34 ($0.40 per kwh tier 3). The same 100,000 BTU for gas and 80% effiiciency costs $1.56 ($1.25 per therm teir 1).

The break even is about $0.26 per kwh which is below tier 2 pricing so you really need to be in tier 1 pricing for the heat pump to look more cost effective which is nearly impossible with a pool and AC.

[quantumchromodynamics]

I have found heat pumps to be quite slow at heating. During cold weather, they can struggle to keep up with losses if you don't have a cover.

For example, the Jandy AE3000 is rated at 135,000 Btu per hour output with a C.O.P (Coefficient of Performance) of 5.92. That corresponds with an energy usage of 22,804 Btu per hour, which equals 6,683 watts, which equals 29 amps at 230 volts.

As your outside temperature drops, the C.O.P also drops. I think that the 135,000 Btu per hour output is overly optimistic for real world use. As the outside temperature drops, the heat loss rate from the pool water increases. Both factors mean that heat pumps are not a good choice for colder climates.

Ground Source Heat Pumps work better, are quieter, more effective and more efficient than air source heat pumps.

Another option is to use an electric heater, such as Coate's 24 kW heater. 24 kilowatts = 81,891 BTUs per hour. The primary problem is cost of operation and power supply requirements.

Natural Gas is going to give you the best performance. It is fast and reliable.

Solar has the advantage of giving you lower operating costs, but won't always be able to keep up if you like the pool to be really warm.

Using a dual heater system, like Richard does, can give good performance and lower operating costs.

I think that your best option is solar and gas

[chem geek]

Note that some automation systems, like the Pentair IntelliTouch that I have, do not allow for simultaneous use of both solar heat and gas at the same time (they are on different automated temperature sensing programs that cannot operate simultaneously). That's very unfortunate since there are some times when I'd want to get faster and less expensive heating during the day from both. Instead, I need to use the gas at night if I want the pool warm in the early part of the day. If I could have both, then the solar could help heat up from the somewhat lower temps and gas would help at the same time and carry over when the solar stopped due to cooler air temps. This sort of situation is what occurs during the edges of the season when there is still sun, but the air temp is cooler. Use of glazed solar panels would work better in this situation, but are around 3 times as expensive as the unglazed standard flat black plastic mat Fafco panels I use. A comparison of solar technologies is discussed in this thread.

[sjpoolowner]

Thank you so much for all the help! Yes, now I understand how tiering can play a role here. Will definitely look into solar heating. Thanks again.

[Pool Clown]

The Pentair IntelliTouch that I have, do not allow for simultaneous use of both solar heat and gas at the same time (they are on different automated temperature sensing programs that cannot operate simultaneously).

Richard, I know of a work around for this if you don't have one already.

[shanemiller]

Ya i think solar heater is gonna be of great benefit to us.The heat pump is not that useful.

[gQhuynh12]

I know these posts are from awhile ago, but I’m wondering if we have electric solar panels would it make sense to be the heat pump?