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I was wondering what y'all do to conserve/cut your energy costs in the Dallas area. I have picked up bits and pieces of information on this in various threads but I think the topic is worthy of its own thread. Things I am curious about: Difference in energy bills between single story and two story houses, energy differences in older homes vs. newer homes, effectiveness of replacing major systems with newer systems like AC/Furnace, any experiences with a rain cache for grey water use, on the spot water heater system in place of a traditional water heater, solor panel experience, etc.
Thanks in adavnce!
I assume that solar panels are a bit risky here with the hail that can come in the spring. A few baseball size hail stones and you're out a few grand at least.
I looked into wind power and found some really cool vertical axis turbines that were inexpensive, but it's not quite windy enough here. Out in Amarillo it would be well worth it, but here it's only windy enough from December - March.
The best thing that I can think of is looking at your attic. If you have batt insulatation, look at the R value and make sure it's at least R-38, but the DoE suggests R-49. If you have blown-in insulation, measure the depth. Often times the installer will blow in say 12" and 3 years later it settles to 9", reducing the R value. You can get bags of celluose insulation at Home Depot and they loan you the blower for free, and you can top it off t R-49 inexpensively.
The other thing to consider is a radient barrier. The best option is often the most complicated unless you are going to replace your roof. They make decking with the foil already attached to the underside. If you re-roof and use that and go with a lighter color shingle, you'll see some savings. You can also put up a foil in two ways... against the rafters, or lay it on top of your insulation. If you lay it on the insulation it loses some of its reflectivity due to dust after 5 years or so. If you put it up against the rafters it won't collect as much dust, and it keeps the whole attic cooler, which further reduces the load on any air handlers if they're also in the attic. The big catch with putting the foil against the rafters is ventilation. If you have soffit vents and don't have a ridge vent, you will block the airflow within the attic and create major moisture problems. The real solution would be to block all gable or other vents, install a ridge vent and make sure your soffit vents are adequate... then apply the foil.
There's another option, but I haven't ever gotten a straight story on... and that's radient barrier paint. I don't know if I can believe all the hype because the companies that do it often offer a package deal. They bundle the paint installation with blowing in 12" of insulation... so if your energy cost goes down, how do you know what actually worked? I hear the foil is close to 95% effective while the paint is often closer to 40-60%...
Another thing to keep in mind is to plant some shade trees on the south facing side of your house. Not only will it make your landscape more beautiful, it takes some of the stress off your a/c.
I'll start with overly generic items, then work deeper into things.
First off, efficiency repays itself over and over well before actually generating power (with solar, wind, etc). With that said, an efficient home begins with siting.
PROPER SITING
By siting, I mean the orientation on the lot and things such as shading. To begin with, the best orientation of a home is north-south - with a majority of the windows on the south and north sides. On the south, deciduous trees (drop leaves in the winter) are the best. Since afternoon sun in the summer is so glaringly hot, having trees to shade the West side of your home is a bonus.
# of Stories
Single story homes are more efficient than multiple stories. The reason for this is pressure and air differences. We all know that hot air rises. As hot air rises, if it is trapped, it creates pressure. In a perfectly sealed home, you could actually measure pressure differences. Theoretically, if your home had 10' ceilings, the pressure at 5' would be the same exact pressure as it is outside. Go higher, and the pressure rises; lower, and the pressure drops. The further from that center point, the greater the pressure differential from the outside. If your house is 20' tall (2 stories), the center point will be further from the floor of the 1st floor and further from the ceiling of your 2nd floor. 3 stories... even stronger pressures are in play.
Pressure is also in play in the summer, during the "cooling" season, but is to a lesser extent than the "heating" season. We do indeed have both in North TX.
LIGHTING
As is discussed everywhere, compact flourescent lighting uses less energy. This is a given. What I want to discuss here is actually related more to air leakage.
Many homes have recessed, or "can" lighting. Many of these lighting fixtures are rated "non-IC", meaning insulation cannot contact it. If this lighting is installed in a ceiling that is exposed to an attic (i.e. anywhere in a 1-story - or in the upper floor of a multistory home), this lighting is creating a highway for conditioned air in your home to escape. In the pressure section, I discussed higher pressures as you go higher in a home. Imagine having the highest pressure at the ceiling, then having a lighting fixture that actually has holes drilled in it (which is exactly what non-IC rated recessed lights have). It's the equivalent of drilling a hole in your ceiling. Very bad for efficiency. It's actually quite inexpensive to have an electrician replace them. Recessed lighting itself is not bad, just replace all non-IC rated fixtures with "IC-Rated" systems.
INSULATION
As listed above, the Dept of Energy (DOE) recommends R-49 insulation in the attic. After you've had your non-IC rated fixtures replaced, go ahead and upgrade to this level. There's not much you can do with an existing home about wall insulation. It is what it is. You're not going to pull down the brick to change it.
HVAC Equipment
I'm not going to go too deep here, but basically the rating you want to look at is SEER. Higher is better. 13-SEER is the federally mandated minimum and is dramatically better than it was 5 years ago. 16-SEER is pretty darned efficient, and there are units up to 19 at this point. I haven't personally seen any traditional cooling equipment with a higher rating - but as the technology continues to improve... expect this number to go up.
The only other piece I'd like to hit on equipment is the air handler. You can get multispeed air handlers and multispeed or dual stage compressors. The concept is that you don't have a traditional air conditioner that is either "ON" or "OFF". Instead, it has two settings - a "LOW" and a "HIGH" setting. By running in LOW (which is more efficient) most of the time, it pulls out more humidity, so your home feels more comfortable and the equipment isn't cycling on and off all the time - making it last longer. Both are good!
Tankless Hot Water
These things are quite small compared to a regular 40- or 50-gallon (or higher) unit. They heat water when it's demanded. Otherwise, it sits and does nothing (compared to a standard tank that has to keep the entire tank hot all the time). It does save some money from a monthly bill perspective, but to be completely honest - I have one and I don't think it saves all that much. What's REALLY nice about them is that you never run out of hot water. If you need to run 10 people through a shower back-to-back... so be it. The last person gets a shower just as hot as the first. Possibly if a person does a lot of traveling, where their house sits for a week at a time... that would be the person to see the greatest return on such a system. They are a wonderful item to have in your house and have two side benefits: being smaller, can be relocated into the garage or attic to free up a closet if yours is located in one and they last something like 20 years - so in the long run, the high upfront cost to install one is recouped.
At this point, my fingers are getting tired and dinner is done, so I'll be back later to hit on windows and new-vs-old construction.
Old -vs- New home
Most builders of new homes don't do much more from an energy conservation perspective than they did in the 70's, other than what the gov't requires (13-SEER HVAC in particular). Although it is relatively common now to have Tyvec or some other sort of home wrap that helps to stop air from moving through the wall. With that said, it's actually pretty easy to get the utility bills of a old home under control.
If we assume you have a well sited home that is in the 2500-3000 sq ft range, but hasn't been made more efficient, you'll easily see $600-700/month cooling bills in summer. Spending $7-10K on a new HVAC (16-19 SEER, dual-stage) and spending $1000-1500 to increase the attic insulation will very quickly get that bill down into the $250-300 range in june-july-aug.
If I were to put the items in order of greatest return, my top two items would be as follows:
1. Insulation and "IC-Rated" cans - these two go hand-in-hand
2. New HVAC - min of 15-SEER and dual-stage/speed
These two items alone will easily halve your peak electric bill in the summer and drastically decrease your heating bill in the winter. After that, plant a tree or two on the South and West side of your home. If you want to replace the windows, go ahead. From an energy perspective alone, they won't pay for themselves, but if you are replacing some old aluminum single pane pieces of *@*#, the combination of increased resale value and energy savings may pay for itself. We're in the process of doing this, but we're doing it as a combination of aesthetics, sound attenuation, to lower our bills and making a conscious effort to do what is right to decrease energy usage to minimize our contribution to global warming. It helps that I do all the installation, so they do become more affordable.
Hope all this info helps.
Personally, I would rather see a person that is aware of all these issues buy a used home and give it an energy efficient makeover. Many people are simply unaware or just don't care. Buy a home that you can make nearly as efficient as a new one and help it! You can make more of a difference in our area than increasing the efficiency of a relatively efficient new home.
Thank you all for your input.
We haven't bought a house yet, but we will in the near future. It is important to us that our house be as energy efficient as possible. We have no qualms about fixing up an older home. We want a single story and we are looking for nothing bigger than 2200 square feet because we really don't need anything bigger than that. (Right now we live in a tiny 2 bedroom 1 bath house that is less than 1000 square feet, 2000 sounds like a mansion to us!!!) Thank you for educating us on all these different aspects!!
Thank you all for your input.
We haven't bought a house yet, but we will in the near future. It is important to us that our house be as energy efficient as possible. We have no qualms about fixing up an older home. We want a single story and we are looking for nothing bigger than 2200 square feet because we really don't need anything bigger than that. (Right now we live in a tiny 2 bedroom 1 bath house that is less than 1000 square feet, 2000 sounds like a mansion to us!!!) Thank you for educating us on all these different aspects!!
When we were looking for a home, we looked at the info tag on the existing HVAC equipment. Many manufacturers put a manufacturing date on them. Ours home had an almost 17 year old unit when we bought it. Knowing this up front allows you to negotiate, as you can ensure your inspector checks the input-vs-output temps at the register. Use this to negotiate a better price, since you'll have to drop a chunk of money into a new system.
2200 sq ft is a good size for a home - plenty to handle a family, yet not so big it's hard to heat/cool (and furnish - upsizing from half that will indeed seem like a mansion).
I wish you the best of luck - if you have any questions - feel free to PM me.
Tankless Hot Water
These things are quite small compared to a regular 40- or 50-gallon (or higher) unit. They heat water when it's demanded. Otherwise, it sits and does nothing (compared to a standard tank that has to keep the entire tank hot all the time). It does save some money from a monthly bill perspective, but to be completely honest - I have one and I don't think it saves all that much. What's REALLY nice about them is that you never run out of hot water. If you need to run 10 people through a shower back-to-back... so be it. The last person gets a shower just as hot as the first. Possibly if a person does a lot of traveling, where their house sits for a week at a time... that would be the person to see the greatest return on such a system. They are a wonderful item to have in your house and have two side benefits: being smaller, can be relocated into the garage or attic to free up a closet if yours is located in one and they last something like 20 years - so in the long run, the high upfront cost to install one is recouped.
I had one of these in Japan when I lived there many years ago.
THEY ARE FANTASTIC. Cheaper to use, take up very little space, and you never run out of hot water. I highly recommend getting one installed.
Like other cool bathroom stuff in Japan, we need more of those things here! I guess there are a few drawbacks. People have said that it takes longer to get the hot water and that a lot of the heat escapes through the pipes, but I personally never noticed that at all. We had a Bosch unit in Japan.
lh_newbie... Thank you for sharing your knowledge with the rest. That is fantastic information. Would you happen to know anything about Millenium windows, they claim to use highly insulative glass, so you don't have to run into breaking a seal and having ugly condensation.
This is an item that comes up in almost every home inspection and I would love to learn if there is a permanent fix for it.
Highly insulative glass? Sounds like a load to me.
Windows
Windows come in many sizes, shapes, materials, etc. Ignore all that. Materials are basically irrelevent - you get the material you like aesthetically. Some people love wood. Some people like white vinyl. While Vinyl technically insulates better, this is all taken into account when rating the windows with specs. There are three ratings you need to pay attention to:
SHGC - Solar Heat Gain Coefficient. Lower is better. Represented as a decimal number of less than 1. This is the percentage of solar heat that makes it through your window. Old single pane glass with no coatings would allow 90% or more of the heat into your home. Not good. This would be represented by a number of 0.90. A good quality, dual pane window with low-e coating will have a number of 0.35 or lower. New low-e coatings, such as Low-E366 is bringing this number below 0.30 - I've seen them as low as 0.27. Awesome!
U-Factor - Insulating rating. Lower is better. For those of you familiar with R-values of insulation, this is basically an inverse of that number (just to make things more confusing for home owners). So an R-value of 2 would equal a U-factor of 0.50; R-value of 3 is a u-factor of 0.33. A good window will have a U-Factor less than 0.35.
VT - Visual Transmittance. This is the percentage of VISIBLE light comes through a window, represented as a decimal number. 0.75 means 75% of the visible light makes it through. Since low-e coatings block solar heat gain (a portion of the spectrum of light - ie UltraViolet and InfraRed), it does block some visible light. A typical rating is roughly 0.60, give or take.
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