Thread: Water Heating Device

Came across this device this morning which I'm not familar with or have ever seen.

It was connected to the refrigerant lines to a Heat Pump. It had water supply lines which ran up and across the attic and dropped down to an electric water heater. It had some corrosion present on the lines and the obvious missing insulation on the lines.

Can someone explain its operation.

Thanks,
Rick

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That's a Heat Recovery Unit ... best energy saver ever invent (other than the 'OFF' switch, that is).

Heat taken from inside via the refrigerant is taken from the refrigerant coil in there, transfered to a water coil in there, the heat in the water is then circulated to the water heater and heats the water in the water heater, the cooler water in the water heater then circulates back to the heat recovery unit coil, and, while that is happening, the refrigerant is taken to the condenser unit and through the condenser coil, with all that heat being wasted and blown into the outdoor air.

What was done is to capture 'free heat' for the water heater, heat which would have been dissipated to the outdoor air.

I had one on our house down in South Florida, the water heater seldom came on as the a/c kept the water hot.

It works with a heat pump during the winter also, except that instead of capturing 'waste heat' is it taking some of the heat being pumped into the house and heating the water with it. The occupants of the house would likely never notice the slight reduction in heat available to the house, and in return, they get 'free' hot water when the heat pump or a/c is operating.

I'm surprised you guys in Texas don't install them all over.

Jerry,

Thanks for the info. It sounds like a great idea but I've never seen one. I would maybe expect to see something like this on a upper end home but this was on a very small foreclosed home under 80K.

You'd think they would be more popular with the rising costs of utilities.

Rick

Originally Posted by Rick Hurst

I would maybe expect to see something like this on a upper end home

Nah, upper end homes don't care what it costs to heat, cool, provide hot water - not in the realm of things they think about.

Right again JP, its us poor folks who should be investing into those types of appliances for our homes to save us money.

We've got those darn things all over Central Florida. Most are disconnected when the A/C or water heater is replaced due to leaks, damage, or un-informed technicians.
I don't like they save as much as originally thought. Very few, if any, new HRU's installed.

Originally Posted by Dom D'Agostino

Most are disconnected when the A/C or water heater is replaced due to leaks, damage, or un-informed technicians.

Just the opposite in South Florida, most are still working.

The ones I've seen disconnected were ones where the condenser unit had been replaced and the tech must has scratched their head and just disconnected it, not knowing what it does.

I've *never* seen one leaking.

I don't like they save as much as originally thought.

Hmmm ... everyone I knew who had one, including myself, knew how good they were. Many people turned their water heater breakers off.

If you can turn the breaker off to the water heater and still keep hot water, they've got to be doing something, right?

What is it they say ... about of 1/3 of your electric bill is for heating the water in the water heater ... (I actually think it's less than that, but even 1/4 or 1/6 is significant ... $200 per month with it makes that $66 at 1/3, $50 at 1/4, $32 at 1/6 in savings per month when not running the water heater on electric.)

Mr. Kelly,

I think your on the wrong thread.

rick

Originally Posted by Jerry Peck

What is it they say ... about of 1/3 of your electric bill is for heating the water in the water heater ... (I actually think it's less than that, but even 1/4 or 1/6 is significant ... $200 per month with it makes that $66 at 1/3, $50 at 1/4, $32 at 1/6 in savings per month when not running the water heater on electric.)

I doubt that. Progress Energy and Florida Power & Light both supply info that, when calculated, equals less than $1.00 per day to heat an electric tank, or $23-$30 monthly for the majority of their clients. If you save 30% (30% is a huge savings for any energy saving device) you're saving money, but not that much in total. The device costs $300 plus another $250 for labor. Plumbers can't service them, and A/C techs don't understand them, and homeowners don't "see" $7.00 per month as an issue. I'm sure its regional, but very few people around here turn their WH off just because they have a HRU installed.

Here is a quote from FPL about water heaters and HRUs:

Heat Recovery Units - recycles waste heat from your central A/C so your water heater does not use as much energy to heat water, however, it will only produce hot water on days when your A/C is being used.
These devices may save you money if you have a large family, but they also have a much longer payback period. For example, the average cost of a heat recovery unit is about $600 with a savings of $35 per year for a four-person household, making the payback period 15 years or more.

No wonder most of them get disconnected over time.

Dom.

Originally Posted by Dom D'Agostino

I doubt that. Progress Energy and Florida Power & Light both supply info that, when calculated, equals less than $1.00 per day to heat an electric tank, or $23-$30 monthly for the majority of their clients.

Hmmm ... let me get this straight ...

I used underlining and bold for highlighting purposes

Originally Posted by Jerry Peck

(I actually think it's less than that, but even 1/4 or 1/6 is significant ... $200 per month with it makes that $66 at 1/3, $50 at 1/4, $32 at 1/6 in savings per month when not running the water heater on electric.)

Me: $32 at 1/6 in savings per month

Dom: "I doubt that."

Dom: "equals less than $1.00 per day to heat an electric tank, or $23-$30 monthly"

Me: Okay, so I'm off by 2 bucks or so. YOU think 30 bucks a month is not a significant savings off your electrical bill?

Dom: "and homeowners don't "see" $7.00 per month as an issue."

Me: How'd you go from $30 a month down to $7 a month?

$500 or so on a new home put into the mortgage is not even noticeable, it's less that that $7 a month you say is not an issue.

$500 or so on a condenser replacement is not a real deal killer either, not when you are already spending $2,500-3,000, it's like the a/c contractor telling you 'Oh, yeah, by the way, we found this when we removed your old unit and, to fit the new unit it, we're going to need to blah-blah-blah ... it'll cost about $500 more.' You go 'Ouch!', but know you have no choice, with the heat recovery unit, you go 'At least I'll be getting back $25-30 bucks a month, in just over a year and a half it's paid for.'

Dom: "and A/C techs don't understand them"

Me: That I have to agree with - yet they are soooo simple to understand.

Originally Posted by Jerry Peck

Me: Okay, so I'm off by 2 bucks or so. YOU think 30 bucks a month is not a significant savings off your electrical bill?

I'll was going to re-type what I already posted, but I'm not interested in debating the math. Slow down when you read.

You can't save what you don't spend, it simply doesn't cost that much to run the WH. Re-read FPL's quote above.