We Turned Off Our Natural Gas!

 We turned off our natural gas meter this month, and we just paid our final bill with the gas company!

All major systems in our house are fully electrified, and we have a high-efficiency wood-burning stove as an additional heat source!

We still have a number of effficiency gains we can make, but it feels good to savor this accomplishment :-)

Charging Area for Robots and Laptops

We have one of those desk nooks in our kitchen. We've never been really sure what to do with the space. But recently I installed a new electrical outlet in the foot-space, and now we have a charging barn for our robot vacuum and robot mop, and charging cables in the drawer below the counter, to keep our family laptops in a known location that's also unlikely to be swept to the floor by accident.

Since the robots are pushed foward and easy to access, I think I might install some sort of shelf above robots and below the drawer - might make a good spot to store our instantpot or something similar...

Heat Pump Water Heater

 Our 10-year-old natural gas water heater had about reached its life expectancy, and it was the last thing responsible for us paying money to the gas utility every month. We replaced it this weekend with a heat-pump hybrid electric water heater! A Rheem Proterra 50 gallon tank, in our case. It has both standard resistive heating elements, and a heat pump (hence "hybrid"). The resistive elements draw 4500 watts when you need heat in a hurry, but the heat pump draws only 400 watts. Interestingly, at 400 watts, a heat-pump-only version of this tank could easily run on a standard 120 volt 15 amp electrical circuit.

We have been working towards this since we replaced our natural gas furnace with a ground-source heat pump, but supply chain issues and life in general meant we kept the natural gas water heater for an entire extra year.

First we drained the old water heater and removed the exhaust flue:

I had to be careful of the coolant lines for the ground-source heat pump. Pretty inconvenient that they run down the middle of the mechanical room like that.

Then I wrangled the new water heater into place and plumbed it up.

Extra stuff: there's a 2" foam pad between the concrete and the tank, both for thermal insulation and vibration isolation. Then a drain pan to catch any stray water and direct it away from the pad toward the floor drain. I have a "heat trap" loop on the hot water output, to prevent convection or thermosiphon heat losses. There's a thermostatic mixing valve to prevent scalding, and an expansion valve (rather than a bulky expansion tank) which routes to a plastic vinyl tube manifolded with the condensate drains from the ERV and the heat compressor on the water heater. 

The Proterra tank is also an Internet of Things device, so I can schedule heating to run when our solar panels are likely to be producing extra electricity. I can also monitor how much hot water is in the tank, which has been my current pointless obessession since I installed the tank. The tank also reports how much electricity it consumes, but that hasn't really agreed well with the energy tracking I've done with my Emporia Energy monitor. I've seen other complaints about the energy reporting not being very accurate, so I'm going to give the benefit of the doubt to Emporia.

The old water heater used 12-14 therms of natural gas in a month, which is equivalent to about 350-400 kWh of electricity per month. We're on track to use about 60-70 kWh of electricity per month with the new hybrid water heater after the first week.

One tricky part is that we're planning to add a second "desuperheater" tank (already purchased, and taking up space in our finished basement) to scavenge heat from the ground-source heat pump and preheat the cold water before it goes into this tank. So the plumbing isn't final. But that will wait until the old natural gas piping is removed, to make room for the second tank.

https://precisioncomfort.com/home-comfort-product-choices/new-homes/heating-cooling-comfort-options-new-homes/geothermal-option-what-is-a-geothermal-desuperheater/

Switching to a Heat Pump Clothes Dryer

As part of our on-going electrification efforts, we replaced our natural-gas powered clothes dryer with an electrically powered heat-pump clothes dryer. This also entailed the final bit of new flooring installation, as I only wanted to move these appliances once.

First up was removing the washer and dryer, and removing and capping-off the natural gas line that went to the dryer:

That was followed by removing the old linoleum and plywood:

Then came laying down the last bit of LVP and patching the vent hole:

Here's what happened on the outside of the house:

And here's the final product:

We gave away the old natural gas dryer, so it can give more years of service rather than taking up space in a landfill.

The dryer is a Whirlpool WHD560CHW ventless heat pump clothes dryer, with a 7.4 cubic foot capacity, which pretty much matches the capacity of our washer and previous dryer. So far it does seem to take about 25% longer to dry, but I don't think I would have noticed if I hadn't been timing things.

Now we just have to replace our natural gas water heater with an electric model, and we will be able to have our natural gas meter disconnected!

Thinking About Residential Grey Water

While working on using less resources as a family, we have mostly focused on reducing electricity and eliminating fossil fuels as a household. But here in Colorado, plain old water is actually becoming a scarce resource.

We dealt with this a little bit when we installed a DIY on-demand hot water reciculation pump in the master bathroom. And it looks like just that change reduced our water consumption by about 15% year-over-year. Once I had water conservation on my brain, I started thinking about reusing grey water. 

Grey water is typically sourced from bathroom sinks and showers, and clothes washers, usually requiring you to use specific soaps, shampoos and detergents. The grey water is then used to water landscaping or flush toilets.

Our drainage plumbing doesn't distinguish between sinks and showers vs toilets, so that's a non-starter forus. However, I do have several sources of "clean" grey water that currently go straight to a drain:

• Condensate from the ground-source heat pump
• Condensate from the Energy-Recovery Ventilator
• Drain from the clothes washer
• Drain from the (future) heat-pump clothes dryer
• Drain from the flush cycle of the water softener

Of these, the condensate drains are probably too miniscule to bother with, although I haven't actually measured. The really interesting one (to me) is the flush cycle of the water softener. Right now, all that water goes straight down the drain. In my house, I think I can plausibly use that water to help refill the toilet tanks in two bathrooms, with minimal plumbing work. I'll have to stick a bucket under the water softener flush drain and see what kind of flow rates I get, and how cloudy the water is.

Geothermal Check-in - Winter

The heat pump is doing great! You can see on the left side of this photo that we got down to -13°F this morning, but we still haven't seen the emergency resistive heater kick on. Looks like all the insulation upgrades and new windows are paying off and we have a fairly resilient system! 

Garage Roof Insulation

We've been noticing that the roof of our garage isn't insulated very well. 

We're clearly losing heat through it, and since our heat is from a ground source heat pump now, it feels more precious.

Materials are hard to come by at this point in Covid-times, but we were able to get some rolls of appropriate insulation after waiting 2 months for delivery. I put up the insulation, and now the snow stays on our garage roof for days and days, instead of melting immediately and leaving frozen puddles on our driveway.