In the endless effort to improve the home’s efficiency and reduce contributions to climate change, I took on replacing the water heater with a heat pump water heater. There were a few reasons for this, and the stars aligned to make it happen.
- The previous gas water heater (40 gallon Ruud Guardian) was installed in 2009 and was 15 years old, making it towards the end of its life. We had never done any servicing on it.
- Home Depot was having a deal on a 65 gallon Rheem Heat Pump Water Heater. It was cheaper than the 50 gallon version.
- I had the time.
There’s a lot of hype about heat pump water heaters. They’re super efficient. They do it by working like a refrigerator in reverse; using surrounding air to heat the water, dumping cold air outside. For this reason, it’s best to have the water heater in a large room. It also makes noise when it’s running, just like a refrigerator. The previous water heater was next to the furnace because of the proximity of the gas line and the venting to the old chimney. This resulted in an extra 20′ of copper pipe for the hot water to cool down in. The new water heater would go next to the water softener, where it would be in the laundry room and have a larger space from which to draw warm air, plus it would eliminate that 20′ of copper pipe, meaning hot water faster, and less wasted water.
I ordered the water heater, which took a couple weeks to be delivered to Home Depot. I also applied for the permits, and ordered the other accessory components for the installation. I spent a lot of time worrying about the noise level, and trying to figure out whether I should put insulation underneath. In the end, the noise level isn’t an issue, and the insulation is recommended in WA and CA, and just about any styrofoam will do because the actual PSI on top of it is way below its rated pressure. Rheem does have a 120V plug-in heat pump water heater, but it doesn’t have a heating element, and isn’t recommended in northern climates, so I was forced to get the hybrid one that has backup heating elements.
Moving Day
Getting it physically in place was not easy. It’s 300 pounds empty, and very bulky. I rented a truck from Home Depot, and they were able to use a lift to get it up there vertically. I strapped it down, then drove it home. Getting it off the truck was the first real challenge. I used 2 2″x6″x12′ boards stuck through the pallet and eased it off the truck, then slid it down the boards until it made it onto the driveway. Then I put it on top of the boards and slid it up three stairs up to the side door. Then it was over the threshold and to the hardest part; getting it down a flight of stairs. For this I was an idiot and stood under it while I tipped it and slowly lowered it down a step at a time. If I had lost my balance or lost control, it would have been a very expensive and possibly very painful mistake, but fortunately nothing bad happened and I got it down the stairs and to its final location just fine. I had to lift it again to get it on top of the styrofoam, but that wasn’t terrible, either. Once there, I was finally done moving it.
Plumbing
I didn’t have the tools necessary for copper pipe work, so I recruited my friend across the street, who came over and cut the old pipes off and installed a bend and new pipe for the new connections. I had ordered water heater hoses with push to connect ends from Amazon, and installing them was trivial and worked just fine. However, the inspector asked for specifications, and it turned out the internal diameter of these hoses was less than 3/4″, which would restrict flow and was therefore not acceptable. I returned them and got SharkBite fittings and cables instead, and was able to install those myself. It was a little wet to do it, but it worked just fine.
Electrical
The wiring was easy. I drilled holes through joists and pulled the wire through, stapling it where required. I put in the box above the water heater and ran some cable through the liquidtight conduit down to the water heater. I even installed the breaker without shutting off the panel. I’ve been in there so many times, and it’s not a difficult installation, so I wore some insulated gloves and installed the circuit breaker last.
Other Installation
The water heater generates condensation, so a drain pipe is necessary. I debated PEX and CPVC and PVC, for a while. CPVC is coming out of favor, but would have been easy. PEX requires a crimping tool I don’t have. PVC is a little more expensive, but didn’t require any special tools, so I went with that. I was able to get it to slope gently all the way to the utility sink, solving the problem without a pump. The pressure relief tube was off the shelf and just needed to be screwed in. I also zip tied it to the drain pan.
At the bottom of the heater is a plastic drain pan. It’s not required, but it wasn’t expensive, and might be a nice thing to have in an emergency, especially since the foam is underneath it. The foam is just normal 2″ styrofoam. I did the math multiple times, figuring out the compressive strength of the foam, the total weight of the heater with water, divided by the surface area of the bottom, and ended up with a huge safety margin, so I have no worries. I don’t know if it will ultimately prevent any heat loss into the ground, but it is something that’s recommended (but not required).
Results
Now that we’ve had it running for about a month, we’re starting to look at the data. During the summer months, our gas consumption was about 10 therms per month, which is roughly 300 kWh (I use the summer months because the only other consumer of gas is the furnace, which isn’t running during the summer). For the month we’ve had it, the new water heater has consumed 100kWh, and seems to be doing about 3kWh/day. It’s a much bigger tank, and because of its proximity to the house fixtures we get hot water much faster. The laundry room is noticeably colder by a few degrees, and the noise is barely detectable outside the room; less than the furnace. We’ll see how much power it consumes in the summer, when it should work more efficiently.
While there are some rebates available in Wisconsin, they require installation by approved distributors. I didn’t get that, but I did save a bunch of money by doing it myself. Instead, I’ll have to rely on the 30% of project cost rebate through the Energy Efficient Home Improvement Tax Credit. Ultimately it’ll cost about $1400 for the project, which is significantly more than a gas water heater replacement. Over the course of the lifetime of it, it might break even.
Total Costs
| Product | Purpose | Cost |
| Total: | $2051.24 | |
| Rheem Performance Platinum 65 Gallon Smart High Efficiency Hybrid Heat Pump Water Heater | The water heater | $1623.65 |
| NM Liquidtight Flexible PVC Conduit Whip | Conduit to go from the electrical box to the water heater | $20.02 |
| Home Depot Truck Rental | Getting the water heater from Home Depot to Home | $20.05 |
| 2″x2’x4′ R10 Styrofoam | Insulation for under the water heater | $5 |
| 4x4x2″ metallic electrical box with knockouts + cover | Terminate the Romex, switch to liquidtight to connect to heater | $4.11 |
| SharkBite 3/4in Push to connect to 3/4in FIP 24″ braided connector | 2 – one for hot water and one for cold | $31.96 |
| SharkBite 3/4in Push-to-connect Ball Valve | Shutoff for cold water | $28.97 |
| Tan wing nut connectors | electrical connections for fat wire | $5.98 |
| Square D 30-Amp 2-pole GFCI | Power supply for the water heater | $57 |
| Romex 10/2 NMB 25′ | Cable from the heater to the breaker box | $47.15 |
| Brass pipe | New ends to connect to the existing water lines | $12.18 |
| Drain pan | Sits under the water heater | $12.98 |
| Temperature & Pressure relief pipe | $4.98 | |
| PVC tubing for condensation drain | $27.21 | |
| City permits for plumbing and electrical | $25 each. Since a new circuit was being added, and the water heater is moving to a new location in the basement | $50 |
| Labor | 1 hour of assistance with disconnecting water pipes and connecting new pipe | $100 |