7 ms·

I've had mine for about a year. I put it in my garage which previously, would reach easily 100F + in the summer. This past summer, on the hottest day, it got

I've had mine for about a year. I put it in my garage which previously, would reach easily 100F + in the summer. This past summer, on the hottest day, it got to about 90 in the garage. When the water heater was running, it easily kept the garage below 90. I purchased the hybrid version which can use straight electricity when the heat pump won't cut it. This serves to also keep the garage cooler for the second fridge I have in the garage. I was previously on propane to heat my water, which was costing between $50 - $60 a month. During the summer, my electricity bill only went up $12 a month. During the coldest part of winter, it was at about $30 a month more. But, I pay considerably less for electricity in the winter than in the summer. Just for reference, I purchased the Rheem 65 gal 10 year warranty from Home Depot when it was on sale. This has definitely been one of the best purchases

mrfusion 6y ago
50$ a month for hot water seems really high? I’ve never gone over 20$. Anything you want to tell us?
- dsfyu404ed 6y ago
  Water usage basically scales with household size. GP probably isn't a single dude living in a studio apartment taking navy showers and planning his meal prep to minimize dish washing. Combine that with an electric water heater (almost always more expensive to run than natural gas) and a nearly triple digit electricity bill isn't surprising.
- amluto 6y ago
  Propane, I’d guess. With propane, you are paying someone to truck propane to you and pump it into your tank. You are also paying all the costs of owning and maintaining the tank. If you live in a place with reliable electricity, I don’t think propane really makes sense any more. You can get heat and hot water from heat pumps, and induction stoves work well and are vastly more efficient than gas.
  - oflannabhra 6y ago
    In rural areas, where propane is common, with some density (1-5 acre lots), lots of places converted to natural gas after the fracking boom. That’s not to say that propane is still not common.
    - mrfusion 6y ago
      You get natural gas delivered? What’s so special about propane anyway that it’s the defacto portable gas?
      - koolba 6y ago
        It’s liquid at ambient temperatures under pressure so it transports and stores well. Also it’s a tad more energy dense than natural gas.
      - kube-system 6y ago
        Propane has higher energy density, can be liquified by compression, and doesn't need cryogenic tanks.
      - ridgeguy 6y ago
        Propane is easily transported and stored as a moderately pressurized liquid at ambient temperatures. Propane has a big volumetric advantage over natural gas. Natural gas is mainly methane, liquifies at -160°C, and requires active refrigeration. If your use point is within natural gas piping range, gas is usually the better choice. Propane is the choice for locations not served by piped natural gas.
    - mirimir 6y ago
      Fun factoid: Propane leaks are far more dangerous than methane leaks. Methane is less dense than air, so it tends to mix more fully. But propane is more dense than air, so it tends to pool near the floor. And the lower flammability limit for propane is lower (2.1% vs 5.0%). So you reach the lower flammability limit faster. Plus the fact that pilot lights are often near the floor.
  - 6y ago
- lutorm 6y ago
  Before we a) put in PV and b) got that heat pump water heater, we paid about $50 for our hot water heater electricity use (~160kWh/month) here in HI.
duskwuff 6y ago
Wow, I'd never considered that aspect of a heat pump before. But it makes sense -- a heat pump is (conceptually) just a backwards air conditioner, after all; it stands to reason that it'd make the room colder while it's operating.
- SilasX 6y ago
  My thermodynamics book in college (Cengal and Boles?) had a (Blondie) comic with The exchange: “Are you air-conditioning the outside?” ‘No, I’m heating the house!’
nkurz 6y ago
I replaced our older electric water heater with the 50 gallon version of this last month: https://www.homedepot.com/p/Rheem-Performance-Platinum-50-Gal-10-Year-Hybrid-High-Efficiency-Electric-Tank-Water-Heater-XE50T10HD50U0/300620237 https://www.homedepot.com/p/Rheem-Performance-Platinum-50-Ga.... The heater was about $1200, the rebate from the state of Vermont was about $800. I did the install myself with about $100 of parts. Positives: As far as I can tell so far, the savings in electric usage should pay back within 2-3 years. It has a 10 year warranty, which should keep it working for a while. If the compressor fails, there is an electric element as backup. The device itself seems solid and well built. Negatives: Even though it's in the basement, it's louder than I'd like --- about like an window air conditioner. Getting it down the narrow basement stairs (and getting the old heater out) was hard. Reheat is fairly slow if you keep it on the highest efficiency "heat pump only" setting. I've yet to get the phone app working to control it from upstairs. The basement is quite cool (especially in winter) so I'm worried it won't be maximally efficient. It produces a small amount of condensate water, which requires a drain of some sort. Overall, I'm hoping it will be a win. It produces enough hot water for our 2-person needs, and seems like it should be more efficient than what it replaced. If you are considering one, it's worth thinking about the cooling effect that it will have on the room that it is in. If you already run an air conditioner, this is a win. If you are heating, this is a loss. We heat with wood in the winter (which is inexpensive if you cut your own) and don't have any other summer air conditioner, so for us this aspect is fairly neutral.
- deleted 6y ago
  [deleted]
- ortusdux 6y ago
  This model can be ducted with standard 8" ducting. It is possible to have it draw warm air from outside or vent the cold air out of the house. You can get fancy and install baffles that you switch seasonally. A properly ducted system will be more efficient because you won't be putting artificial house heat into the water or heating the house more to offset the cooling.
  - nkurz 6y ago
Cthulhu_ 6y ago
I wouldn't try and cool down a garage or try and maintain a temperature in it to be honest, they're usually very poorly insulated so it'd be a huge waste of energy.
ag56 6y ago
Wouldn't it be great if your fridge could integrate directly with the heat pump, rather than indirectly via the air in an enclosed space? In summmer, our (California) home frequently has the air-conditioning running mid afternoon, at the same time as a gas boiler is heating the pool. It would seem to make sense to use the pool as a giant heatsink for the home AC... but that doesn't exist apparently, and any plumber I talk to looks at me like I'm crazy. "They are separate systems."
- energ8 6y ago
  From my reading of heat pumps, mismatches in energy sources and sinks can make linking things together more complicated (aka more expensive) than is commonly available. For the pool <-> A/C case, This Old House did a segment on linking the systems: https://www.youtube.com/watch?v=J7fB8ul9dZw https://www.youtube.com/watch?v=J7fB8ul9dZw Edit: chris_va has more details about why linking systems is hard: https://news.ycombinator.com/item?id=23001888 https://news.ycombinator.com/item?id=23001888
- matheusmoreira 6y ago
  Would be great if everything was integrated. Computers for example generate a lot of heat. Would be great if we could easily move that heat to places where it is actually useful instead of just wasting it. Looks like this is a thing in data centers: https://en.wikipedia.org/wiki/Temperature_chaining https://en.wikipedia.org/wiki/Temperature_chaining > It would seem to make sense to use the pool as a giant heatsink for the home AC... but that doesn't exist apparently, and any plumber I talk to looks at me like I'm crazy. You are not crazy. IBM did that. https://en.wikipedia.org/wiki/Green_data_center#Reusing_waste_heat https://en.wikipedia.org/wiki/Green_data_center#Reusing_wast... > The IBM Reusing Data Center in Switzerland, where the heat warms a local swimming pool Also: https://en.wikipedia.org/wiki/Data_furnace https://en.wikipedia.org/wiki/Data_furnace
- diggernet 6y ago
  It does exist, and those plumbers are wrong. The biggest challenge is finding a heat exchanger (to replace the one in your AC condenser) which is designed to survive highly corrosive hot swimming pool water. The UCDavis Western Cooling Efficiency Center [1] has done extensive research on this, sponsored by the California Energy Commission. In a nutshell, they found that using your swimming pool as a heat sink for your air conditioner can reduce cooling energy consumption by 30% or more (not including the reduction in pool heating energy consumption). The two main caveats: 1. Many pools are too small relative to the house to be an effective heat sink without overheating the pool. 2. Increased pool temperature causes increased evaporation, resulting in increased water consumption (also a problem in CA). They also found that adding a fountain for evaporative cooling of the pool can mitigate #1, at the expense of worsening #2. [1]https://wcec.ucdavis.edu/ https://wcec.ucdavis.edu/

mrfusion 6y ago

50$ a month for hot water seems really high? I’ve never gone over 20$. Anything you want to tell us?

dsfyu404ed 6y ago
Water usage basically scales with household size. GP probably isn't a single dude living in a studio apartment taking navy showers and planning his meal prep to minimize dish washing. Combine that with an electric water heater (almost always more expensive to run than natural gas) and a nearly triple digit electricity bill isn't surprising.
amluto 6y ago
Propane, I’d guess. With propane, you are paying someone to truck propane to you and pump it into your tank. You are also paying all the costs of owning and maintaining the tank. If you live in a place with reliable electricity, I don’t think propane really makes sense any more. You can get heat and hot water from heat pumps, and induction stoves work well and are vastly more efficient than gas.
- oflannabhra 6y ago
  In rural areas, where propane is common, with some density (1-5 acre lots), lots of places converted to natural gas after the fracking boom. That’s not to say that propane is still not common.
  - mrfusion 6y ago
    You get natural gas delivered? What’s so special about propane anyway that it’s the defacto portable gas?
    - koolba 6y ago
      It’s liquid at ambient temperatures under pressure so it transports and stores well. Also it’s a tad more energy dense than natural gas.
    - kube-system 6y ago
      Propane has higher energy density, can be liquified by compression, and doesn't need cryogenic tanks.
    - ridgeguy 6y ago
      Propane is easily transported and stored as a moderately pressurized liquid at ambient temperatures. Propane has a big volumetric advantage over natural gas. Natural gas is mainly methane, liquifies at -160°C, and requires active refrigeration. If your use point is within natural gas piping range, gas is usually the better choice. Propane is the choice for locations not served by piped natural gas.
  - mirimir 6y ago
    Fun factoid: Propane leaks are far more dangerous than methane leaks. Methane is less dense than air, so it tends to mix more fully. But propane is more dense than air, so it tends to pool near the floor. And the lower flammability limit for propane is lower (2.1% vs 5.0%). So you reach the lower flammability limit faster. Plus the fact that pilot lights are often near the floor.
- 6y ago
lutorm 6y ago
Before we a) put in PV and b) got that heat pump water heater, we paid about $50 for our hot water heater electricity use (~160kWh/month) here in HI.

duskwuff 6y ago

Wow, I'd never considered that aspect of a heat pump before. But it makes sense -- a heat pump is (conceptually) just a backwards air conditioner, after all; it stands to reason that it'd make the room colder while it's operating.

SilasX 6y ago
My thermodynamics book in college (Cengal and Boles?) had a (Blondie) comic with The exchange: “Are you air-conditioning the outside?” ‘No, I’m heating the house!’

nkurz 6y ago

I replaced our older electric water heater with the 50 gallon version of this last month: https://www.homedepot.com/p/Rheem-Performance-Platinum-50-Gal-10-Year-Hybrid-High-Efficiency-Electric-Tank-Water-Heater-XE50T10HD50U0/300620237 https://www.homedepot.com/p/Rheem-Performance-Platinum-50-Ga.... The heater was about $1200, the rebate from the state of Vermont was about $800. I did the install myself with about $100 of parts. Positives: As far as I can tell so far, the savings in electric usage should pay back within 2-3 years. It has a 10 year warranty, which should keep it working for a while. If the compressor fails, there is an electric element as backup. The device itself seems solid and well built. Negatives: Even though it's in the basement, it's louder than I'd like --- about like an window air conditioner. Getting it down the narrow basement stairs (and getting the old heater out) was hard. Reheat is fairly slow if you keep it on the highest efficiency "heat pump only" setting. I've yet to get the phone app working to control it from upstairs. The basement is quite cool (especially in winter) so I'm worried it won't be maximally efficient. It produces a small amount of condensate water, which requires a drain of some sort. Overall, I'm hoping it will be a win. It produces enough hot water for our 2-person needs, and seems like it should be more efficient than what it replaced. If you are considering one, it's worth thinking about the cooling effect that it will have on the room that it is in. If you already run an air conditioner, this is a win. If you are heating, this is a loss. We heat with wood in the winter (which is inexpensive if you cut your own) and don't have any other summer air conditioner, so for us this aspect is fairly neutral.

deleted 6y ago
[deleted]
ortusdux 6y ago
This model can be ducted with standard 8" ducting. It is possible to have it draw warm air from outside or vent the cold air out of the house. You can get fancy and install baffles that you switch seasonally. A properly ducted system will be more efficient because you won't be putting artificial house heat into the water or heating the house more to offset the cooling.
- nkurz 6y ago

Cthulhu_ 6y ago

I wouldn't try and cool down a garage or try and maintain a temperature in it to be honest, they're usually very poorly insulated so it'd be a huge waste of energy.

ag56 6y ago

Wouldn't it be great if your fridge could integrate directly with the heat pump, rather than indirectly via the air in an enclosed space? In summmer, our (California) home frequently has the air-conditioning running mid afternoon, at the same time as a gas boiler is heating the pool. It would seem to make sense to use the pool as a giant heatsink for the home AC... but that doesn't exist apparently, and any plumber I talk to looks at me like I'm crazy. "They are separate systems."

energ8 6y ago
From my reading of heat pumps, mismatches in energy sources and sinks can make linking things together more complicated (aka more expensive) than is commonly available. For the pool <-> A/C case, This Old House did a segment on linking the systems: https://www.youtube.com/watch?v=J7fB8ul9dZw https://www.youtube.com/watch?v=J7fB8ul9dZw Edit: chris_va has more details about why linking systems is hard: https://news.ycombinator.com/item?id=23001888 https://news.ycombinator.com/item?id=23001888
matheusmoreira 6y ago
Would be great if everything was integrated. Computers for example generate a lot of heat. Would be great if we could easily move that heat to places where it is actually useful instead of just wasting it. Looks like this is a thing in data centers: https://en.wikipedia.org/wiki/Temperature_chaining https://en.wikipedia.org/wiki/Temperature_chaining > It would seem to make sense to use the pool as a giant heatsink for the home AC... but that doesn't exist apparently, and any plumber I talk to looks at me like I'm crazy. You are not crazy. IBM did that. https://en.wikipedia.org/wiki/Green_data_center#Reusing_waste_heat https://en.wikipedia.org/wiki/Green_data_center#Reusing_wast... > The IBM Reusing Data Center in Switzerland, where the heat warms a local swimming pool Also: https://en.wikipedia.org/wiki/Data_furnace https://en.wikipedia.org/wiki/Data_furnace
diggernet 6y ago
It does exist, and those plumbers are wrong. The biggest challenge is finding a heat exchanger (to replace the one in your AC condenser) which is designed to survive highly corrosive hot swimming pool water. The UCDavis Western Cooling Efficiency Center [1] has done extensive research on this, sponsored by the California Energy Commission. In a nutshell, they found that using your swimming pool as a heat sink for your air conditioner can reduce cooling energy consumption by 30% or more (not including the reduction in pool heating energy consumption). The two main caveats: 1. Many pools are too small relative to the house to be an effective heat sink without overheating the pool. 2. Increased pool temperature causes increased evaporation, resulting in increased water consumption (also a problem in CA). They also found that adding a fountain for evaporative cooling of the pool can mitigate #1, at the expense of worsening #2. [1]https://wcec.ucdavis.edu/ https://wcec.ucdavis.edu/