I have been looking at this product for the better part of two years and I'm very happy to say we have finally got one installed! I am very happy with this product and am equally happy to supply one of the first reviews of it. I know one of my own biggest uncertainties was the dearth of reviews out there: Will my pool get too hot? Will it work at all? The heating and cooling needs are not matched. The summer is hot already, etc. With no reviews, we basically had to just take the plunge. I hope this sheds some light onto the product, how it works, and will help someone else with their pool heating decision.
The Hotspot FPH heat reclamation pool heater, website here, is a device that connects to your central AC unit and redirects the waste heat from your house back into your pool. So, instead of the giant fan on the outdoor AC unit spitting the waste heat from your house into the sky, the Hotspot FPH unit instead puts the heat into your pool water.
It does this by running the hot AC refrigerant coil through a small canister through which your pool filter connects and sends the water through. Essentially, it heats the flowing water like a tea kettle using the heat from the AC coil.
I will update this post with pictures in the coming days.
Here is an album with some pictures of the install: Hotspot FPH build - Album on Imgur
The whole concept of this product really appealed to us. In fact, we went searching for this solution over two years ago before we knew the product even existed. I stumbled onto it quite accidentally when watching an episode of Ask This Old House which featured this product. The appeal is just how complimentary the two systems are -- in the summer, you want to cool your house AND heat your pool.
One more thing to note before jumping into the review is that I live in the northeast, where the summers are warm and the spring and fall are cool. I am not looking to extend our swimming season with a pool heater. I know several households with more conventional propane or heat pump pool heaters who don't extend their season either, since in the northeast, it is astronomically expensive to do so, even for an additional month on either end of the Summer.
Rather, we are looking to maintain a warm and consistent pool temperature during the swimming months from late June to early September. Our pool will naturally get to 80 degrees from ambient heat and sunlight alone, assuming there is a nice stretch of no rain. That's not bad, but it's not ideal either. We're looking to keep the pool at or above 84 degrees consistently, rain or shine, during the summer swimming months.
The Hotspot FPH pool heater will do just this. Unfortunately, we just got this installed at the tail end of this swimming season but I can report my results as of now. When installed two days ago, my pool temperature was 78 degrees. The water coming from the return after being heated was 2.5 degrees warmer than the regular pool water -- 80.5 degrees. Since the pump can filter all the water in the pool once every 8 hours, we can ideally heat the pool by 2.5 degrees every 8 hours. Obviously, this will depend on AC use as well.
As of now, my pool is at 80 degrees and rising. This is pleasantly surprising even to me, considering how cold the nights have been around here lately. I'm hoping we can get it above the 84 degree mark by the end of September, but I don't think we'll hit it this late into the season.
The concept of this heater is a bit different than conventional heaters. A conventional heater is absolutely massive, capable of heating a pool 10 degrees or more in a few hours. A typical heat pump pool heater can supply over 100,000BTUs/hr of heat to the pool. My 3 ton home AC when paired with the Hotspot unit can supply 36,000BTUs/hr of heat to the pool. However, where a conventional pool heater is only meant to be run a few hours at a time, intermittently, home ACs are designed to run more frequently and more consistently. This means that the Hotspot FPH heater will heat the pool more slowly and respond more slowly to shocks in pool temperature. But, since it is run frequently, it is ideally suited to maintaining a set pool temperature.
If, like us, this is what you're looking for in heating a pool, then this unit will be perfect for you as well.
To get into the nuts and bolts of the install, the unit consists of two parts: a blue canister that sits on the ground and has 4 connections, 1.5" water in, 1.5" water out, and two refrigerant lines, one hot (input) one cold (output). The other part is the controller unit that gets mounted to your house.
The water lines divert through the pool heater in the typical way: right after the filter and before returning to the pool. If you're really handy, you can probably do this yourself. I hired a plumber.
The refrigerant lines get split and connected to a 3-way valve, to either be cooled by the normal fan unit, or by your pool water. The system is fail-safe, in that if power is cut to the FPH controller unit, the AC system defaults to fan cooling. I had *many* questions about the operation, safety, and handling of edge conditions with regard to this rather complex setup that I won't go into here, but if you have any questions I would be happy to answer them. The bottom line, however, is that the Hotspot engineers are pretty smart guys, and have thought about all these cases already and developed a nice, safe, reliable product that I'm confident is not going to break my pool or my AC system.
In fact, I have no doubt my AC system is going to operate more efficiently now that it is water cooled. It is wild to see my house AC on without the fan on. The outdoor unit is MUCH quieter! And the refrigerant lines leaving the water cooling canister are distinctly cooler than when they are fan cooled.
In fact, my HVAC guy had his equipment set up reading the pressure gauges of the refrigerant lines between air cooled and water cooled modes. When air cooled, the pressure was 300psi. When water cooled, the pressure was 100psi. The translation of this that I got from my HVAC guy was that the compressor was working much less hard when the refrigerant is water cooled than when it is fan cooled, meaning it uses less energy and will extend the life of the compressor. Obviously, the fan isn't going either which saves somewhere around 300-500 watts of power as well from what I can tell.
The controller unit takes in electrical connections, 120VAC home current to power itself, and takes in 240VAC lines for your pool pump, so that it can turn on and off your pool pump regardless of the pool pump's timer settings. I know more than I strictly need to now about how that all operates and if, like me, you have questions regarding this I will be happy to answer them.
The controller unit also takes in low voltage wires from the compressor to control fan usage and when operating in water vs air cooled modes. With the controller unit off, the system defaults to fan cooled mode. Fail safe by design.
The installation costs were high but not surprising, considering I live in the northeast.
The FPH unit cost $1800.
Plumbing cost $500, $250 labor, $250 materials. I had about 60' of additional PVC runs to make.
Electrical was $500, $300 labor, $200 materials.
HVAC was $1200, $800 labor, $400 materials.
Total cost was $4,000.
I was eager to share with you my experience with the install and operation of this pool heater, as there is a lot of interest out there, a lot of theories of whether it will work, whether it will heat the pool at all, or overheat it, etc, and virtually no reviews of an actual install out there. I hope this helps some of you who may be thinking about installing such a system for your own pool. I would not hesitate to do so again. Every time I see an AC unit spitting perfectly good warm air into the sky I think what a shame, it could be put to such good use.