Tuesday, July 22, 2008

Powering down, Part 2

In order to reduce your electricity usage, you've got to know where it's going in the first place.

You might be saying, "Duh!" right now. Much of this series of posts might make you say "Duh." But I know I can be blind to the blindingly obvious sometimes. And hopefully there's plenty of non-obvious information here too.

There are several ways to approach this project of reducing electricity use. One way is to make a list of all the stuff in your house that uses electricity, and do some quick searches on The Google to get a rough idea of how much each item uses. If that sounds daunting, then just start by tackling a single room. It goes pretty quickly. Just look around at each item, and ask yourself a) do you really need it, b) do you need it plugged in all the time, and c) is there a more efficient - even non-electric - way to accomplish the same thing. I'll cover these ideas in the next post.

Another useful approach is to focus on the biggest energy hogs. That's what this post will cover. The top electricity users will vary depending on your family size, climate, and other factors, but in general, the biggest energy users, starting at the top are:
- Air conditioning
- Water heating
- Electric space heating
- Clothes dryer
(then a huge drop off...)
- Refrigerator
- Stove / oven
- Chest freezer
- Lighting & small appliances
- Computer(s)
- DVRs
- Everything else

A good rule of thumb to use is that if something is using electricity to make things hot or cold, it's likely to be a power hog.

There are plenty of other things that could make their way up the list. If you've got a hot tub, a heated pool, a big plasma TV, a giant collection of A/V equipment, a high-performance computer network, or a basement full of hydroponics... well, you'll just have to figure it out. In our case, we've got a well pump that uses more power than you might expect.

It could be that you don't have electric versions of some of these things. Our hot water and our range both use propane, and we heat with corn & wood pellets, so that gets us out of some big ticket items on the electric bill.

I don't generally advocate buying your way into efficiency - especially while the economy is hitching a ride with the Ty-D-Bol Man. I mean a hybrid in every driveway and a solar panel on every roof sounds cool, but where's that $100 grand per household come from anyway?

New stuff takes energy to manufacture and transport - sometimes more energy than you'll save by buying it. We have to think of the whole life cycle, not just the monthly meter reading.

But there are times when buying new will pay off big enough to justify it. In the US and Canada, many large appliances come with big yellow EnergyGuide tags to give you an electricity usage estimate. If you need to replace an appliance, definitely consider paying a little extra up front for a more efficient model. In fact, I'd recommend going to the EnergyStar web site to research. I mean, how often do you get to take advantage of a government program that's actually useful and easy to access?

Keep in mind that some appliances like dryers and ovens don't have EnergyStar ratings because, well, in terms of electricity, they're all about the same. The best and worst electric ovens will be very close in energy usage. Well, unless you've got ten grand to buy a range with a magnetic induction cooktop and a convection oven. (I'm sure it's worth every penny...)

So enough conceptual. Let's get to some details.

Here's a bar graph showing the top energy users at our house (assuming typical usage, not actual usage):
There are a couple interesting things here. First is the massive difference between the top two and the rest. With a family of five living on livestock-infested mud farm, we go through a lot of laundry. So by looking at our estimated numbers, it becomes obvious that we'd get an extra large payoff from using a clothesline instead of a dryer. And we do.

(Just for the record, the dryer usage on the graph was based on the number of loads of laundry we typically do. If you make a graph like this, it will probably look different. And in fact, my own estimate may be way off, because I'm playing fast-and-loose with some of the calculations. But it's a starting point.)

The graph also makes it obvious that keeping our house cool in some way other than central air is going have major benefits. The big red 2006 lines in the center of yesterday's graph demonstrate the same thing.

Now I'm not going to tell you that we haven't used our air conditioning at all this summer. We've just used it very sparingly. We've found quite a few strategies for keeping the house cool sans A/C. I'll try to summarize what's worked for us.

First, you've got to get the cool night air into your house. Check the weather forecast to see what the low temperatures will be overnight. When our daytime temps are in the 90's, overnight lows are still usually down in the mid 60's.

Think about that: Free 65 degree air. You need to take advantage of it.

Open windows when you're going to bed. Stick some fans in a couple bedroom windows, blowing inward. Even if it's a little warmer outside when you go to bed, don't worry about it. That night air will cool off before long. Then when you get up to a nicely cooled house the next morning, close the windows to hold that cool air in and keep the hot muggy summer at bay.

We recently installed a Tamarack HV1000 whole house fan to draw that cool air in.
Now the typical whole house fan uses a lot less electricity than an air conditioner, but it also creates what amounts to a giant hole in your attic insulation. Just because those metal louvers are closed doesn't mean they're keeping the heat out in summer, or the cold out in winter. If you have one, find a way to insulate it, at least in winter. Climb up in the attic, put some cardboard over it and throw a couple batts of insulation on top. Or maybe cover it with plastic.

he Tamarack model we got is two smaller fans side-by-side. They fit between standard ceiling joists so it's a little easier to install. It draws a good bit less power than a standard whole house fan, so it takes a little longer to get that cool air in (maybe 10 minutes vs 2), but really, speed is not that important to the process.

It also has insulated doors that close when it's not in use. The standard model comes with R-22 insulation, but for a little extra, you can get R-38. It's not the cheapest fan, but we were lucky enough to have some extra cash to play with, so it worked for us.

Besides sucking cool night air into your house, it will push the super-heated air out of your attic space, which will reduce the amount of heat seeping into your living space from above. Attics can get to 140 or 150 F on a sunny 90-degree day.

Next, if you live in a seasonal climate, you want shade on your south-facing windows in summer (but not in winter). So if you don't have any, plant some leafy trees right now. I planted some cherry trees this year. Or build a trellis or an arbor to shade your south-facing windows, and grow some vines. I like multitaskers, so I'm using grapevines. You could also consider hardy kiwi, or if you're into homebrewing, try hops.

Don't forget about your west-facing windows too. There's a reason why the late afternoon sun is sometimes called the Dragon Sun. The sun will be lower in the sky when it gets to your western windows, so take that into account when planning for shade.

While you wait for those trees and vines to grow, you can block the sun with window coverings. Dark curtains, honeycomb or cellular shades, quilts backed with Reflectix or similar... plenty of options here. This approach can be effective, but it has a small flaw. You're stopping the sunlight (and it's accompanying heat) after it's already gotten into your house.

We've advanced the battle lines to the other side of the glass. I bought a roll of Phifer Suntex 80 shade screen. (I don't know that the brand is important - that's just what I got.) People in the Southwestern US have probably known about this stuff for ages, but it was a fairly recent discovery for me. This is like regular window screen, but made up of more "screen" and less "hole". It blocks out 80% of sunlight before it gets to the window. I'll explain exactly what we did in more detail at a later date, because I'm not quite using it in the typical fashion. But to answer the question you're probably thinking, no it doesn't make it dark inside the house.

Another important factor for keeping cool is to make sure your house is well insulated and well sealed. Track down a copy of Insulate and Weatherize by Bruce Harley. This book does a great job of covering the concepts, but also the how-to if you're so inclined. I'd like to add more blow-in insulation to our attic spaces at some point, though ours is pretty good already.

Anyway, just by bringing in the cool air at night and keeping out the sunshine during the day, our house stays as much as 15 degrees cooler inside, and even on the very hottest days, we can often avoid air conditioning until 4:00 or 5:00 in the afternoon, until dusk. Often we can avoid it altogether.

Oh, one more trick: If you have a basement, seriously consider using it. Ours was a wreck for a long time, because our 20+ year old sick and senile cat treated it as one giant litter box-slash-vomitorium. But as he has gone to the great catnip field in the sky now, I spent a lot of time cleaning up our unfinished basement to get it into a semi-usable state. And boy does it feel nice down there on a warm day.

Next time I'll go over the many other smaller changes that have added up to quite a bit of savings.




At 7/23/2008 12:00 PM, Blogger thenn said...

Thanks for taking the time to put this together! Also thanks for the tips on my cantaloupes, if you were closer I would brind you one of my reclaimed melons (assuming I pull this off).

At 7/24/2008 11:27 AM, Blogger katecontinued said...

Great post, very informative.

At 7/25/2008 6:38 AM, Blogger Carolyn said...

Just stopped by for a visit. I wanted to say Hi and nice Blog!


At 7/25/2008 8:22 PM, Blogger e4 said...

Thanks, y'all!

At 7/29/2008 4:08 AM, Blogger LisaZ said...

Very interesting post. Thanks.

At 8/05/2008 9:49 AM, Blogger Owlfarmer said...

Thanks for "pimping" the whole-house fan idea. Even here in north Texas (where our temp has hovered around 107 for the last few days) I use my double-decker attic fans to suck in cool air in the morning, then turn off one of them, close off two rooms (bedroom and study) and turn on the window units set at 83. When the outside temp stays down around 100, we can actually stay cool in the house (85 years old, solid wood pier & beam construction) without the A/C, using ceiling fans only after the morning cool-down. It's important not to draw heat into the house during the hottest part of the day (say 1 pm until the sun goes down).

These are great tips--glad I found the blog. Also cool that you're a Whedon fan . . .

At 8/11/2008 10:54 AM, OpenID eatclosetohome said...

I found the fastest way to get cool air into the house at night is actually to blow the fan OUT the window, especially if you open another window to the outside. This creates a vacuum inside the house and sucks the cool air in from the outside, rather than trying to stuff more cool air into a room full of hot air.


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