Tag: energy savings

Energy Usage – Update

We’ve been tracking the energy draw of our various appliances since getting our geothermal system a few years ago. It was great to see the diminished usage with the geothermal system, but I’d like to reduce our usage farther. Not just to save money on our bill and reduce our impact, but reducing our draw will reduce the number of solar panels we’ll need to support our home.

The items we’ve audited so far account for 88.46% of our energy usage in the past year — the oven, cook-top, microwave, bathroom exhaust fan/heater, lighting (we installed LED bulbs several years ago), and misc small plug-in devices (tools, small appliances, laptops/tablets, phones) are 11.54% of our usage. While I’ll certainly make improvements wherever possible … I’ll see a bigger savings cutting the septic aerator usage in half than completely eliminating the untracked draw. The biggest savings comes from investigating the top of the list.

HVAC is still our biggest draw. We’ve dropped the temperature rather significantly in winter without seeing much decrease in usage, so just changing the thermostat isn’t a big win. I’ll be building a thermal imaging camera with a MLX90640 IR sensor — it’s a cool toy, and I’d be able to identify thermal leaks. Unfortunately, I picked a really bad time to look for thermal imaging bits. All of the temp checks we’re seeing to identify coronavirus infections? Thermal imaging everything is on backorder. I put my order in, so I’ve got a place in the queue.

The water heater … I’m going to spend more time investigating why our desuperheater doesn’t seem to do much. We’ve seen savings in the winter — when I’d expect to see the least benefit from the desuperheater — and nothing in the summer. I want to research insulating some of the water pipes and installing heat traps. And we’ll finally purchase the “smart” controller that hooks up to the WiFi and lets you drop the set-point on a schedule.

Next largest draw is an old refrigerator — that’s an easy change. We’ve got a newer unit that needs some repair. One year of energy savings will just about pay for the part, so it makes sense to retire the old fridge and bring the broken one back into service.

Those changes, plus fully shutting down the old server, should reduce our power consumption by about 4,500 kWh/year — a 450$ savings, and a significant reduction in solar system sizing.

Item kWh/year
HVAC 4932
Septic 4668
Water heater 2676
White refrigerator (1989) 2250
Car charging 1164
Black refrigerator 1134
New server 1103
Dryer 245
Family Room TV 144
Dishwasher 118
Bedroom air filter 61
Water pump 53
Washing Machine 30
Downstairs bedroom TV 12
Raven charging 7

And, hopefully, we’ll finally hit the ‘efficient neighbors’ line 🙂

Controlling Printer Outlet

We normally keep our printer turned off. Residential printer standby can have a decent draw. It’s something you have to research specific to your printer — some have low single-digit standby draw and waste ink when powered on and off. Others, like ours, has a non-trivial standby draw that isn’t offset by ink savings. The problem is that you’ve got to turn the printer on, print your stuff, and then remember to turn it off. The tiny person remote power controller (i.e. Anya) works for this, but it’s not an elegant automated solution.

Scott set up a smart outlet for the printer – you can tell the Echo to turn the printer outlet on and off now. But you still have to remember to turn it off 🙂

So I set up a print queue on the server & all print jobs are submitted to the server-based queue. A scheduled task on the server checks the print queue for jobs and turns the printer on when jobs are found. When the printer is on but no jobs are in the queue, it waits ten minutes and checks again (otherwise you could turn the printer on & have the batch immediately turn it off. Or worse the job could be out of the queue but still printing!), then turns the printer off if there are still no jobs in the queue. Voila, now the printer turns itself on when you want to print something and it remembers to turn itself off later.

The tricky bit was figuring out how to post ‘ON’ and ‘OFF’ to the OpenHAB2 REST API. -Body with just the command:

Invoke-WebRequest -URI ‘http://openhabserver.domain.gTLD:8080/rest/items/Outlet1’ -ContentType “text/plain” -Method POST -Body ‘OFF’

The script is available at https://github.com/ljr55555/miscPowershell/blob/master/printQueueMonitor.ps1