Bob
Hi Marcus,

I live in Phoenix, and have a "spool" that is at the most 2500 gallons. I am looking to keep it at a spa temperature of about 101 max, and I don't have a problem ramping up the temp earlier in the day to get the temp to where I want it. So, I have been told by the local pool folk that a heat pump will not work for me, and I need to have a propane heater (no NG at my home)-which I am not willing to pay for that luxury. So, am I expecting too much from a heat pump as a spa heat source, or do you have a solution for me where I will not have a huge electric bill?

Thanks,

Bob
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Marcus Miller
Dear Bob:
Thank you for writing. some gas guys are still prejudice in AZ it seems. Many have not gone to a pool show in 20 years. that is the only excuse that makes sense to me anyway. All heat pumps and gas heaters must heat spas up to 104 / 105 and then shut off for safety reasons. We have some videos of heaters in Las Vegas where nights get to about 30 and days are in the 50's. Some heaters shut off at 50 degrees and some go below that.
Even if you had natural gas at the pool I wouldn't use it as I think gas is too expensive to heat a pool. If the heat pump costs you $50.00 then propane should be $200.00 to $300.00 a month depending on the spot price in AZ. Let me know what you think of the videos.
Sincerely,
Marcus
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Bob
Hi Marcus,

I am glad to see a heat pump will work. The video is good enough proof for me. Here are a bunch of questions for you:

So for my application, what unit would heat up 55 degree water (that's the coldest it pretty much gets) the quickest? Is the highest BTU unit the answer? I obviously want the best bang for the buck. I don't know if I would always keep it running despite reading that that is the most efficient way since the unit would be placed on the outside wall of my master bedroom.

Occasionally the outside temp falls below freezing, so is it worth the extra cost for power defrost? I don't care about cooling the water in the summer since I only use it at night.

My electrial run should be about 100', so is 6 gauge appropriate?

How long would it take to ship to Arizona?

I see some units have an "Arizona" warranty. Is that a good enough reason to go with one brand over the other if overall reliability in the first few years isn't a factor?

Is a 2 point variance in the COP rating significant on electrical savings in your best guestimate?

Thanks Marcus!

Bob
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Marcus Miller
Dear Bob: Thank for writing back. In AZ I like to go a little big on the heat pumps because of the cold nights. Cold nights just sucks the heat out of the pool and then the heat pump runs too long the next day. So keep the heat pump over 100,000 BTU's and use a blanket in cold weather. Most manufacturers bump up the wire size over 100 feet to the next size. They will always say to follow local codes and use a licensed electrician. Some heat pumps need bigger wire than others. It depends on the one that you choose. I or the tech department at the factory can guide the electrician in the right direction. I had a heat pump outside my bedroom for 5 years. I ran it in the day so noise was never an issue. If it falls below freezing out side you need a timer that senses temperature to run the water so that the water doesn't freeze in the heater and void the heat exchanger warranty. Some people just run their water pump 24 hours a day when they get a cold wave. Good if you remember, and you need to hope you don't have a power failure. Shipping is about a week. We ship on the expensive trucks that have a lift gate (not a tail gate as I have seen advertised elsewhere which means nothing) Some heater have a 2 year warrant in AZ where they have 1 year elsewhere. I like at least two years as that is when the heater will have an issue is in the second year. Then they are usually go to go for many years after that. COP is important. I don't think the most important thing though. Any heater in the 5 range is considered good in the heat pump world. the most important think is reliability. This should be a fun thing and not cause you stress. Then I like company reputation, years in business, warranty, efficiency and price. About in that order. A heat pump that defrosts is good. Even if you never use the cooling feature. The Heat Siphons work well in low humidity area with no defrost. They will shut down when they get too cold and then restart when it gets into the 50's. So if you have a spa and you want to jump in when it is 45 and the heat pump had shut off when it got too cold then you won't get the spa warm. In that situation a defrosting heat pump is better. It is always better to heat in the day, as they are more efficient unless you get a break on the electrical rate at night. Some area in AZ get about 50% their day rate. I hope that helps and that I hear from you soon.
 
Sincerely,
 
Marcus Miller
360 568 3718
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