Energy Savings in Newer Houston Homes
This page explains what I’ve learned, what we’ve tried, and what is on the list to try. Costs and savings are estimated on the projects we’ve completed.
General Information:
Your home stays warm and cool in two main ways. First you wrap your home in insulation, this is like putting on a wool coat in the winter. Then you seal up all the cracks which is like putting on a leather coat or a wind breaker. Both play a large part in keeping heating and cooling costs down.
So where is your home on heating and electric usage?
Most sources report about 7 KWh per square foot per year in the Houston area for electric usage in homes that do not use electric heat. A high efficiency home uses 4 KWh per square foot per year.
So if your home is 2,000 sqft and you are in Houston, 2000 * 7 = 14,000 KWh per year makes you average, 8000 super efficient. You can find the KWh on your monthly bill. It is the difference between last month’s meter reading and this month’s meter reading.
We’ve been here a year and so many things made such a huge difference back in NE I did them before we had a baseline. The gas company gave us the monthly numbers from the previous owner, we are using 2/3rds less gas only 33% of what they used. Our electric is down 1/3 from last year and about 1/2 of what our neighbor’s are using. Once we switch out the old refrigerator we will be below 4KWh per sqft, we are very close now.
Lighting: There were incandescent bulbs in all the lights. I replaced all the incandescent bulbs with 15 watt florescent bulbs. They cost about $5 each you can find them as low as $3 on sale or as high as $8. Over 30 light bulbs were switched. Most of these lights get little usage. In Houston you not only get the energy savings from the difference in wattage between the bulbs but the bulbs are not throwing heat the way the old ones do so you need less a.c. Also since some of these lights are 18′ off the floor and need a very tall ladder to reach it is very nice to only have to change them every 5 or so years instead of every 1. You get way more bang for your dollar in Houston, than New-England with the florescent bulbs.
Electric: Turn off lights in rooms you are not using, and turn off the computers at night. Computers are energy hogs but most have built in sleep modes you can put to use. If you have a waterbed, keep it made and put a heavy quilt on top. Anything that does cooling or warming is going to be an energy hog. About 1/3 of the heat in your home comes from appliances. The less appliances on in Houston the better. If you are not using it turn it off.
To figure out how many kWh an appliance is using take amps * 110 volts * hours of use per month. Some appliances have the wattage listed some have the amps. For example my dehumidifier is 7.2 amps. So 7.2 * 110 = 792 watts. 702 watts * 30 days * 12 hours a day = 285120 watt-hours. Divide by 1000 = 285.12 KWh. We pay about .11 a KWh so 285.12 * .11 = $31.36 a month to run the dehumidifier. ‘Kill A Watt’ meters can now be found online for about $25. You plug your appliance into the meter, punch in your rate per KwH and it will tell you how much electricity an appliance is using.
Hotwater: We replaced our 15 year old 50 gallon gas hot water heater that was on high with a 50 gallon HW heater on 120′F. That is saving about 3 therms a month. I’m using warm then cold in the washer instead of hot for both cycles. Also when you reach for the facet, if you are just rinsing your hands or wringing a sponge then use the cold. You’ll turn it off before the hot water would’ve gotten there anyhow. But every time you turn on the hot water facet your hot water heater is going to kick on. So now we are using 9 therms a month for hot water, the stove, grill and the oven. The newer HW heaters do not need blankets they are well insulated. If yours in the attic like mine, the attic is so warm most of the year it likely helps to heat the water.
Windows: We have low end contractor grade windows, single pane on the house now. The money isn’t there to change them out yet, however we did put low e window film on the south west facing windows. Gila Film can be purchased at HD, Lowes and other such type places. It takes the patience of a saint but it otherwise not difficult. Use tons of water, make sure the windows are clean and keep dust away from the film. It is impressive, you can feel the temperature dropping as you are installing the film. We also have 2″ wooden blinds on all the windows. They came with the house and do keep the glare down quite a bit.
Attic: Last December I increased the insulation in the attic to R50. There was only about R12 up there to start. According to most studies this should save 15% off the heating and cooling usage. It cost me about $600 and 3 days of work. Also while I was up there I found several spots where the space between the interior walls did not have plywood over the opening, just insulation. So depending on the time of year, hot air or cold air goes pouring down into the wall space heating up those rooms along that wall in the summer or cooling them in the winter. You want to put down a cover over the space, cardboard, sheet metal wood, what ever works easiest, then put the insulation back over that opening. Seal the edges of the repair with silicon or expanding foam if you can.
Roof: The house still had the contractor grade roof. We re-did it and added roof vents. We still need to add more vents under the eaves. This should make the attic cooler which will make the first floor of the home less warm. You want as much ventilation in the attic as you can but not so much you have critters moving in there.
Doors: Weather strip around the door. On a cool windy day run your hand around the door to find the worst air leaks and seal them. Some source estimate that as much as 20% of the heat leaves some peoples homes through leaky doors.
Cracks and crevices: The insulation is like a blanket, but sealing the gaps is like putting on a wind breaker. Also insulation works by trapping air. If there is a breeze past the insulation it doesn’t do any good. The super efficient homes go so far as to put glue on every nail hole and wrap the home in tyvek when done. An old home may have an 5 air changes over per hour, an efficient one 1, a super efficient a half. An older home on a windy day may have as many as 30 air changes per hour. Engineers recommend a 1/3 air change per hour for healthy air. Sealing gaps is cheap, easy and gives you much more immediate savings than insulation. It is better to seal from the inside so it is painless. Every year after the holidays on a cold, windy day I go around the house, caulk gun in hand sealing cracks. I believe the savings are about 10% a year off the heating bill. What is amazing is that after years of doing this I still find enough gaps to go through a half dozen or so tubes of caulk a year.
Another place I found with big air leaks were all the light sockets on exterior walls. I bought a couple of boxes of the child safety plugs ( ~$2/12 ) and put them in all the outlets that are not being used. This made a big difference on windy days. In this part of the country we have recessed lights in most rooms. They are like having open skylights letting out heat and ac. If you google ‘recessed lights trim kits’ you will find inexpensive kits that have glass or plastic covers. These let much less are out, and they look an awful lot better as well. I put glass covers on all of the recessed lights, the trim kits were about $8 each and after I did the first one I was installing them in about 5 minutes per light. This I think is the reason our heating bill was so 67% lower than than the previous owners. I didn’t add to the insulation till after that had been done and the first few heating bills had come.
You want to seal around all the window and door frames. Seal all the way around each piece of wood, wear cheap gloves, you can get a box of a 100 for a few dollars. Take your finger and run it over the caulk, pushing the caulk into the seam. Then use some of those new throw away cleaning wipes and clean the excess caulk off and you’ll never see it. Be sure to get paintable caulk if you are using it on painted areas, and clear if your wood is stained. Also seal around the baseboards, top, bottom and where ever boards meet, around light and electric outlets and fixtures. The pipes coming into kitchens, baths, and laundry rooms will also need to be sealed. Seal the upper floors first to get the quickest benefit. The expanding foam works great for sealing plumbing penetrations, don’t forget to go outside and seal where the ac pipes and other pipes enter the home as well. Also look for spiders, spiders like drafts so there is likely a leak where ever you find a web. A major leak in most homes is the plumbing stack. This usually runs from the first floor past the baths and kitchen and up through the roof. There is usually a large hole cut around the pipe that feeds cold air down from the attic and drops in in the kitchen and bathrooms. If possible seal the top in the attic and the bottom on the first floor.
Programmable Thermostat: This home already had one. Adjust the floors with no bedrooms on them down at night ( up in the summer ) Or likewise any floor not being used during a specific time. A couple of degrees difference is all you want. Every little bit helps.
LED lights: Right now they are too expensive to put in place of your regular lighting. I did find some Christmas tree strings of LEDs. They ran about 3 times the cost of regular tree light strands ( ~$9/strand 100 lights ). They use ~ 5 watts per strand as opposed to regular tree lights which use about 60 watts per strand. Thats about 21.6 KwH as opposed to 259.2 KwH. They give off no heat. They also do not play well together, so no mixing and matching light sizes and styles or only about half the strands light up. They should last forever ( 100,000 hours/( 24 hours*30 days)= 138 Christmas seasons ).
Summary:
You’ll get the fastest return on your money switching incandescent bulbs to florescent, and caulking gaps. Both are easy enough for anyone to do and the supplies can be found at any hardware store. It is possible to over seal your house. However unless you have a super high efficiency, brand new home to start with it is going to be close to impossible to do so. Each tube of silicon seals a one foot square area 3/16″ deep. Think of having a window or door open that much, it’ll give you and idea of how much you are saving.
Resources:
Build it solar
Useful Energy Conservation Tips
