Category: Uncategorized

The new HVAC system was installed this week and on Monday they put in the new insulation in the attic and did all of the air sealing, including fixing the attic door and sealing the house fan. Today they ran a follow-up blower test to see what difference all of this made. They had missed a couple of things on the first pass, so they sealed around the ash dump door in the back fireplace and installed some weatherstripping on a door. They said the air leakage had improved by 30%. That didn’t seem like that much to me since the house was very leaky before. One thing we found was that a lot of air was leaking from the back room which has wood paneling. Apparently, air was being sucked down from the attic of the back room, down the walls, and out the joints of the paneling. The only way to seal that would be to caulk all the joints of the paneling, overlay the paneling with drywall, or replace the paneling. That would be great, but that’s more than I want to do right now. You could feel a breeze blowing from those joints, but they also had a pretty powerful fan sucking all of the air out of the house. There wasn’t a way to seal from above because that room has a low flat roof that isn’t accessible.
Continue reading “Energy Improvement Results”

I wrote about a self-adjusting timer back in 2008, but only wound up buying one yesterday, once I realized they now worked with compact fluorescent bulbs, and after checking that I had a white neutral wire available in the switch box. I got the Defiant Daylight Adjusting Indoor Digital Timer from Home Depot (model no 49814, store sku is 469637, internet sku is 203678179, UPC code is 43180 49814). I installed it for my front porch light and set it to come on at sunset and to turn off at sunrise. The timer should adjust itself as the days get shorter, always coming on at that day’s sunset and turning off again at the appropriate time of sunrise. It doesn’t do this by sensing light, but by calculating the correct time of sunrise and sunset. But the only things I told the timer were that I lived in the southern third of the US, the current date and time, and today’s time of sunrise and sunset. With some other timers you actually enter the latitude and longitude. I wonder how accurate their approach will be?

Setting it up was kind of a pain. It has all kinds of different programs that can be run for weekends only, weekdays, every day, individual days, Monday-Wednesday-Friday, and Tuesday-Thursday. You can have it come on at specific times or dawn or dusk (others let you have an offset from dawn or dusk, but I think you can overcome this by just entering the offset as the dawn or dusk time; for instance if you want the light to come on at 30 minutes past sunset and sunset is 8:00, just tell it that sunset is 8:30). The 8 triangular buttons you use for setting the time or programs are hidden behind a cover the size of a postage stamp, so it isn’t easy to read what is written on the buttons at all. And the instructions are complicated enough that I’m not sure you could figure it out on your own.

Using the Star Walk app on my iPod, I entered the sunrise time today as 6:49 AM for Atlanta, GA, and the sunset as 8:40 PM. I will check back every now and then and see if it is adjusting like it should.

I’m not sure whether getting new plug-in timers is as compelling. I already have three electro-mechanical plug-in timers that I use to turn lamps on and off. They were cheap and they work fine except they don’t correct for varying lengths of days (so I make adjustments every now and then by turning the dial) and if there is a power outage, they stop and will be off by the length of the outage. To avoid problems with power outages, the new wall switch has backup power, but I’m not sure whether that is a rechargeable battery or a supercapacitor that will hold a charge for a while without power; some other brands use disposable CR2 batteries. The supercapacitor would be best because it would never wear out. I kind of wonder how much energy the timers use. Part of the point is to save energy by turning off the light when it isn’t needed, but compact fluorescents don’t use that much energy anyway. I read somewhere that they may use 4 watts, while the bulb itself is maybe 12 watts. So while the bulb is on, you’re up to 16 watts.

For my back porch, if I were to get a switch, I would probably have it come on at sunset and go off at about 1 AM. Then I could have it come back on at about 6:30 AM when I get up and go off again at sunrise. The problem with that is sometimes the sun rises before 6:30 AM, so it might not get to an off condition until the next day. You can do multiple on-off pairings, so I might be able to get around that by having another on-off program that would turn the light off at 8:30 AM regardless. Well, I checked Star Walk and the earliest the sun rises for the entire year is about 6:25 AM, so I could just have the light come on at 6:20 and then go off at sunrise and I should always be okay, depending on how accurate its sunrise calculation is. If there is a neutral wire in the box for the back porch light, I will definitely get one of these for that switch too.

Date	Sunrise	Timer	Error	Sunset	Timer	Error
7/29/13	6:49	6:49	n/a	8:40	8:40	n/a
8/26/13	7:09	7:04	5 min (25%)	8:11	8:18	7 min (24%)
9/22/13	7:27	7:19	8 min (21%)	7:34	7:56	22 min (33%)
10/26/13	7:53	7:37	16 min (25%)	6:51	7:29	38 min (35%)
11/23/13	7:19	6:53	26 min (29%)	5:31	6:07	36 min (28%)
12/26/13	7:42	7:11	31 min (27%)	5:35	6:11	36 min (29%)
1/26/14	7:39	7:08	31 min (28%)	6:03	6:29	27 min (23%)
2/27/14	7:10	6:48	22 min (27%)	6:32	6:44	12 min (18%)
3/31/14	7:28	7:19	9 min (23%)	7:57	8:07	10 min (23%)
4/27/14	6:54	6:59	4 min (80%)	8:18	8:23	5 min (29%)
5/26/14	6:32	6:36	4 min (24%)	8:39	8:40	1 min (100%)
6/26/14	6:30	6:31	1 min (5%)	8:52	8:59	7 min (37%)
8/3/14	6:53	6:51	2 min (50%)	8:36	8:36	0 min (37%)

When I moved into my house 16 years ago, the furnace was already old, but it worked. The air conditioner was not as old, but it worked too. I had a Georgia Power energy consultant come by back then who said the air conditioner wasn’t that bad. It’s not a name brand of any kind, and I have had to call the repair man a couple of times, but for the most part the system has been pretty reliable. I’m not sure how efficient, but the bottom line is I don’t spend a huge amount on heating and cooling throughout the year, maybe $500 based on the increased usage of power and gas during the summer and winter respectively. So if it wastes energy, it isn’t costing me much.

But when I replaced my refrigerator and started saving a significant chunk of electricity every month, I started thinking I could do better. And that’s true to some extent except that the air conditioner only runs hard for about three months whereas the refrigerator runs all year long. Plus the refrigerator was pretty cheap compared to central air conditioning system.

The other thing is that there are federal tax credits for making your home more efficient, and Georgia Power offers rebates for improvements as well. When I replaced the windows in my house I found that additional cost for meeting the federal tax credits was way more than the tax credit itself and the differences in performance were pretty minor. So for windows I didn’t even try to get the credits, even though the new double pane windows were a big improvement over the original single pane ones.
Continue reading “New Air Conditioner”

A guy came through the neighborhood recently offering home energy assessments. He would do an assessment and then use that data to determine what kind of improvements could be made to increase the energy efficiency of the house, the cost being offset somewhat by Georgia Power rebates and federal tax credits. My air conditioner is over 20 years old and the furnace may well be original from 1950’s. Some of the solutions his company offers are sealing ductwork, adding insulation, and encapsulating crawlspaces, so you kind of know going in what the recommendations are going to be.

Encapsulation means they completely seal off the crawlspace. Usually you want to keep a crawlspace ventilated so that moisture and mold don’t build up, although in winter, when the air is dry, it is okay and maybe recommended to shut the vents (some vents automatically shut during cold weather). With encapsulation the house is sitting on an insulating bubble of air. To keep moisture at bay, they completely seal the dirt floor using plastic sheeting and tape and then glue the edges of the sheeting to the walls and columns. There is already a vapor barrier down of plastic sheeting, but the encapsulation is supposed to be nearly airtight. To keep the bubble of air in the crawlspace from losing heat or cooling, they insulate the inside of the exterior walls of the foundation with an inch of spray foam. Encapsulating like this can be more effective than just putting insulation between the floorboards of the house, which is sometimes recommended (I don’t have any insulation under the floor now). There may also be some amount of air conditioning or dehumidification involved in the encapsulated crawlspace. One nice side effect of encapsulation is it also keeps bugs and other critters out of the crawlspace which has been a problem in the past.
Continue reading “Energy Audit”

I got my new camera today. It was overcast, but the sun wouldn’t set for another hour and a half, so I went ahead and took a picture outside on the back porch. From about 20 feet away, I zoomed all the way in with both cameras aimed at the box the new camera came in. While the Samsung has a bigger and better photo sensor and a higher quality lens, the Canon has a much greater zoom at 10x instead of 2.5x. The Canon claims 14 megapixel resolution and the Samsung 20 megapixels, so maybe the sensor could make up a little for the disparity in zooming ability. Not really. I cropped out 400×300 portions of the pictures taken by both cameras and saved them as jpg files. Here’s the Samsung:

and here is the Canon:

It’s really too ugly a day to much more in comparison, plus the Samsung is kind of complicated, so I need to figure some stuff out. Both pictures have a good bit of noise which isn’t that surprising at full resolution. The picture I took was in smart mode, which is the automatic mode. I do have to manually zoom in by turning the ring on the lens, but it took care of the focus and exposure. Both cameras were sitting on a stool and took pictures on timer so there would be no shaking.

Here is the data from each picture, automatically selected by each camera:

	Canon	Samsung
f-stop:	f/5.6	f/5.6
shutter:	1/13 sec	1/40 sec
ISO:	800	800