The Genius Of Hot Water Heat Pumps

However, my water heater is wearing one additional piece of technology on top … like a hat. It’s a heat pump. That means for every unit of electricity I’m spending I’m getting 3 to 4 units of heat added to the water. It’s way more efficient than any electric or natural gas water heater you can get, but hybrid heat pump water heaters have some quirks and challenges. Also, my setup is a little unique … like … what’s that strange mini-me version of a water heater sitting next to it?

Paul Braren's experience with the Rheem noise issue:

Corrections:
08:49 - I've updated one of the charts used in the video. I converted therms to kWh for the gas vs. electric energy use chart. It's now truly apples to apples, which highlights how inefficient gas is vs. electric. But it also highlights how dirt cheap gas heating is! Updated chart is on my website (link below).

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[scottleepeters]

As an HVAC guy I would like to point out something that is sort of glossed over here that can be a either a benefit or an annoyance mostly based off of climate and location. The concept for a heat pump comes down to moving heat is cheaper than generating it. That heat is coming from somewhere. In a standard heater it's coming from your utility. With this it is coming from your home air which is coming from your heater. I'm in Texas so for the vast majority of time, this is great as we are trying to cool the air anyways. In your situation it's great because you have the most efficient heater available. For someone in a drafty house that already has issues keeping temps in the cold north... Not so much. In our first to situations it is worth the added cost and complexity of more moving parts that will break and are not built to be easily serviced (at least not on the refrigerant circuit side). But this is a minor improvement to be done after focusing on things like passive saving with insulation and upgrading the highest energy consumers like your HVAC system. I do plan on installing one of these at my house and we have done a few for customers with standard water heaters in a hallway closet that vented directly into the houses air. So far so good! We're getting more options for these all the time. Great video and I want to secretly live in your maintenance room!

[SnappyWasHere]

These water heaters in southern climates in garages are amazing. Basically free AC for your garage. Work amazing.

[DerekRoss]

I live in Nova Scotia. I installed a 50 gal Heat Pump Water Heater in 2018 but I didn't remove my old 50 gal Electric Water Heater. Instead I have the cold feed supplying the HPWH and the HPWH feeding the EWH. That way the HPWH does the majority of the heating and the EWH just keeps the water at temperature. Doing that immediately cut my household electricity costs by a third and doubled the amount of hot water available to me. Thus no problems with recovery time. And the basement is well ventilated. So I have no regrets. It's worked very well over the last six years.

[michaelcook]

A few years ago I came across a video of a guy who used a modified water heater tank filled with phase change material that was heated via a solar setup on his roof.
The phase change material had a higher thermal capacity than water and served as a thermal battery for heating and hot water production.
Even though the system is reliant on the it could be boosted with a heat pump in times of need.
Out off all the heating and hot water systems I've witnessed - this guys was the best, most efficient and cost effective I've ever seen. & I've seen a lot... including a farmer using a pile of manure and a coil of copper pipe to produce hot water.

[LouJustlou]

I've had a heat pump hot water heater for three years now. It's the same model as yours. I went from traditional electric to the heat pump and have been saving over $30 a month. I've recovered the investment and it still works great. Mine is in an un air-conditioned garage in FL so plenty of hot air to be had. It's also nice that the garage is a few degrees cooler and has much less humidity. Do make sure to clean the filter. I use a leaf blower on slow speed to blow out the coils once a year.

[chuck]

I had a Rheem heat pump water heater installed in my Florida garage in 2012. Worked great in heat pump only mode year round until the compressor had problems at about the 9 year mark. After the heat pump broke, the unit still worked great with just standard water heater heating elements though until I could get proper support for the device. Long story short, no plumbers want to touch these water heaters for repair. I called Rheem support line and they confirmed that the heat pumps are sealed units with no parts replacements possible. They sent me a brand new unit (which was a nice upgrade too) for free as mine was still under warranty. I was able to get a few bucks at the recycler due to the compressor and other copper parts while turning in my dead unit. Love these things and as I learned, it is nice to have two heating systems built in of one breaks.

[jonathandevries]

Plumber here, i've installed maybe 10 of these...they're pretty cool, downside is the inlet and outlet are on the side of the tank, it makes installation a little tricky to look neat and organized. Also they have an extra step since the condensate needs to be piped to the floor drain....One small downside for end users is that the filter needs to be cleaned once monthly where a tank water heater only needs maintenance once a year.

[svause]

I have run the Rheem for the past five years here in Oregon. We have piped its inlet near to the ceiling of the 12foot-tall garage so as to scrape the absolutely hottest possible air into the system. The exhaust is also pumped into the garage where it is dry enough (the air...) that it quickly dries all the rain which the vehicles track in - and this is in the winter. In the summer, the effect is even more dramatic. Although I've not been tracking its consumption per se, I can assert that it''s quick to recover in either season.

[sspyder]

If you pair your hp water heater in the same room as an inverter/solar system the extra heat from the inverter fans can provide the air heat to supply the room with energy for the water heater to consume. Also keeps the inverter room cool. Thats a symbiotic mechanical relationship

[Bozemanjustin]

6:56 I got to say these heat pump water heaters are a godsend to people in South Florida

You pop one in the garage, and it air conditions your garage so that it's not 140°

Plus being in that hot of an environment, you've got tons of heat for the water

My buddy was going to air condition his garage to keep his car in good condition, but it turns out all he needed was one of these water heaters

Now the garage only feels a few degrees warmer than the house

[traepalmer]

I'm in SoCal and switched to heat pumps for water and space heating last year, and so far, I'm impressed. My water heater is in the garage, which is enclosed but with vents to the outdoors, so for most of the year, it has the added benefit of keeping the garage cooler. I leave it on heat-pump-only during warmer weather and switch to hybrid during cooler weather.

[Spiralem]

Based on the video, it seems like the best value for the Heat Pump system is during Summer where the surrounding is hot and the cool air that comes out of the system is just a bonus.

[JustinDavidow]

For the total water heater results; you also need to include the make-up heat in the home; the heat pump's CoP is driven by the heat generated in the home; so you need to additionally measure the furnace usage increase over the same period. In the case of a ground-source-heat-pump; the additional cost will be in electricity costs (extra pump / compressor / fan time)

[criticaltemperature]

As an hvac professional i "converted" an old dehumidifier into a water heater. I used it for a couple months while replacing my leaking boiler with "tankless coil" to a new boiler with a domestic tank as a zone off the boiler. Being it was DIY its recovery was slow but worked well.

[imurrx]

I used a heat pump water heater in my condo in southern MA due to not being able to vent a natural gas tank. The heat pump tank worked well except with a family of 4, the 4th person would end up getting a cold shower. It was not really an issue since we rarely would do 4 back to back showers. I had to vent the doors leading into the utility room for the heat pump tank to get the air flow needed. It did shave a lot in cost versus the electricity bill ($75/month). The cost to recover to install was about 10 months. The brand was AO Smith. It failed twice in 6 years however. One was a coolant leak and the control board failed. Covered under warranty.

[mattdempsey]

One alternative to combat the space issue is to have a split system approach. We have a BDT Hydrobox which is connected to a regular electric hot water cylinder. The Heatpump system is inside our home, and the external condensor is outside. Then the heatpump hydrobox then pumps hot water into the cylinder

[spyrule]

I have the same model installed this past summer. I live up in Canada. I put mine in the same room as my ventless heat pump clothes dryer, which actually gives off warm air. So my tank takes advantage of that heat source. I also decided to vent my output only, but I put a T on the vent. So in the summer, I dump the cold air back into my basement, and in the winter, it vents outside (using the old dryer vent location). This allows for a very balanced setup. There is only 3 people in my house, so I leave mine on heat-pump only mode, and its saved me almost $50/month compared to my old gas hot water tank. Sadly, I cant do a direct comparison, as I also switched from a gas furnace to a cold-climate heat pump at the same time, so my whole bill is entirely different. Getting PV installed this summer, cant wait to drop my bills to a few $/year.

[daveball]

We had a heat pump water heater for about three months. We swapped it out for an on-demand, propane water heater. There were several reasons:
1. The water heater is in a utility room that shares air with the rest of the house. The utility room was always cold and spilling cold air into the rest of the house. We live in a cold region. We were having to overcome the cold outside *and* the cold from the utility room. I looked into vent kits - simple plastic shrouds from Rheem were over $135 - just for a plastic exhaust shroud. Plus, I'd need to bore a hole through the exterior wall of the house.
2. As the water heater located in an inside space (the utility room) we heard the fan on the water heater - and ours was noisy. We had it reviewed by the installer who told us, "They all sound like that."
3. We are just two people - we now only heat water when we need it.

If we live somewhere warm and the water heater was in the garage, it would be a big, "Yes!" In our situation, the on-demand propane unit makes more sense.

Living in Germany with possibly the most expensive electricity and gas prices in the world, I switched to a similar setup. I don't have an hvac system because we have an old house (Bestandsbau) . My water tank has 3 heat sources, a heat pump, an electric heating element and a loop of copper tube hooked on the old gas furnace. The whole setup is in the cellar which was very cold after a couple of hours of operation. So I optimised the air flow. In summer the heat pump uses very warm air delivered by an air duct from the attic. It presses out the cooled air to the outside world through an opening on the wall. In the winter is the attic cold and the cellar is warm du to the residual heat of the furnace. So the duct is disconnected and I heat the water with waste energy. I also have 10kWp solar with some battery buffer to complete the set up. Of course they are connected with a raspberry pi and controlled with some custom python program that I created.

[commonsense]

There are multiple issues related to this energy analysis.

As some have pointed out, the biggest issue is this heat pump water heater "steals" heat from the house to provide the efficiency gained over electric resistance water heaters. This works very well in homes that are in warmer climates, but not so well, especially in the winter, in colder climates.

Also, natural gas prices have declined in the last 2 years because of the issues associated with war, so the economics associated with natural gas have become much more favorable in recent months. The other issue associated with natural gas, is the way many natural gas rates are structured. Many of the rates have a fairly hefty service charge, with a transportation and commodity charge added for actual consumption. What does this mean? The actual cost per therm of natural gas is even lower than the average, whether using more or less. That means if you use natural gas for anything else in the house, the incremental expense for the additional fuel consumed can be actually quite a bit less, than simply dividing the cost by the number of therms used.

There are several other aspects not considered in this analysis, but too lengthy to go into detail here, (something you learn/exposed to after almost 4 decades in the energy industry).

Anyway, the point I'm attempting to make, whether this heat pump is appropriate for you, there are many other things to consider. As a general rule, if you live in a warm climate, this water heater may be appropriate for you, especially if you have a smaller family and already need to replace your water heater or have a new build. If you live in northern climate and/or have a larger family, this water heater application needs to be analyzed in more detail than presented here, and preferably by someone not selling the water heater, but buy someone who will independently make a complete energy analysis.