On Thursday, April 16, new energy efficiency standards from the National Appliance Energy Conservation Act (NAECA) go into effect for water heaters. Starting that day, manufacturers will only be allowed to make water heaters that conform to the new energy standards. Existing water heaters will still be allowed to be sold, but I don't expect that supply to last for more than a few months, and I've heard those supplies have already disappeared in some areas. Here’s how the changes will affect homeowners.
Side note: Don't call it a "hot water heater." It's just a water heater.
Water heaters under 55 gallons will need to have their energy efficiency rating bumped up just a tad. To do this, manufacturers will be adding about an inch of insulation to the water heater tank. This will increase the diameter of same-capacity water heaters by over two inches, and will increase the height by about one to two inches.
This increase in size won’t be a big deal for most people, but if the water heater is squeezed into a tight space, replacing the water heater could be a hassle, or possibly require replacement with a smaller unit. The diagram below is being used with permission from AO Smith.
Gas water heaters over 55 gallons will need to have an energy factor of at least .74 to .75, depending on the exact size. To achieve this modest energy factor increase, it’s expected that manufacturers will only produce condensing water heaters for these larger sizes. That means a powervent water heater, which needs to have its own dedicated exhaust vent, a power source, and a way to dispose of condensate. These water heaters are obviously more expensive, and the installation costs will be higher too.
Electric water heaters over 55 gallons are about to get silly. For these units, the energy factor is going to more than double. To get there, you’ll be looking at a heat pump water heater. Never seen one? I haven't either.
A heat pump water heater works by extracting heat from the air and transferring it to the water in the tank. Of course, this means it’ll act like an air conditioner in the home. How much will this cool the space it’s in? I don’t know yet, but I've heard it's fairly significant. Here's a nice little video clip from GE showing the amount of energy that these units have the potential to save:
Besides a change in technology, heat pump water heaters will also be significantly taller; somewhere around 18”.
These new units will obviously be more expensive, but the installation / replacement costs should remain the same, assuming they're being installed in a large enough space.
Tankless water heaters won't change much. The energy factor for gas fired tankless water heaters will be going up from .62 to .82, but the vast majority of tankless water heaters produced today already exceed the new energy standard. The energy factor for tankless electric water heaters will remain the same.
Click on any of the links below for more information and specific details on the new water heater standards:
LED light bulbs have been around for many years, but they've been too expensive for me to justify buying. While I know they make a lot more economical sense than a Prius, I've been holding off for the prices to drop down a little further. I finally decided to buy a few last week.
I use the recessed lights in my kitchen more than any of the other lights in my house, so those are the ones that made the most sense to replace. I have 65 watt flood lights, and I probably have them on for about four hours every day - more during the winter, less during the summer. To figure out my annual cost to operate each bulb, I'll assume I pay $0.08 / kWh. The equation is 4 hours * 365 days * .065 kW * $0.08 = annual cost. This makes my annual cost to operate each bulb $7.59.
Two or three weeks ago, Home Depot had a special buy on the 65-watt equivalent LED lights, bringing the price of a 9.5 watt LED floodlight down to $24.97. My annual cost to operate one of these bulbs would be $1.11, making my annual savings $6.48 per bulb, bringing the 'payback' period to a little less than four years.
To really sweeten the deal though, these bulbs are designed to be installed without a trim kit. If you have decent trim kits on your recessed lights, this will mean nothing to you... but I have super-ugly yellow (ok - 'ivory') trim kits on the recessed lights in my kitchen, and I've actually contemplated spray-painting them white or buying new ones, but now I don't have to.
The photo below shows the four new LED light bulbs on the left, and two older incandescent bulbs with ugly yellow trim kits on the right. Those will be replaced very soon.
A common complaint that people have with LEDs is that the color looks blue-ish or cold, but not so with these bulbs. These looks just like the other bulbs in my kitchen - in fact, I think they look even better. I wouldn't even know these were LED bulbs if I hadn't been the one to put them in. The light output is 575 lumens, which is average for a 65-watt incandescent bulb.
Another complaint that people have with LEDs is that they don't dim properly, or they won't dim low enough; not so with these bulbs. To properly dim an LED bulb, the bulb itself needs to be dimmable and an LED dimmer switch needs to be used. After installing an LED dimmer switch, I was able to get these LED bulbs to dim about as low as my incandescent bulbs. I had to wait until night-time to take a photo of this, but I think you'll agree - the light output at the lowest level is quite similar to the incandescent bulbs. The one interesting thing is that at the full dim level, these lights seem to change color - they look a little green-ish.
If you try using a standard incandescent dimmer switch with LED bulbs, it might not work properly. The video below, taken by Milind, shows a good example of what happens when the wrong dimmer is used. This video shows CFL light bulbs, but CFL and LED dimmer switches are the same thing.
If you're not interested in replacing the existing trim kits on your recessed lights, you can buy standard LED bulbs without a trim kit. Costco sells a 65-watt equivalent for about $15, and it looks almost identical to a standard incandescent bulb. I picked up one of these for a recessed light in my bathroom, and it seems to give off the same color as the old incandescent bulb, but it's actually quite a bit brighter. While the packaging called this a 65-watt equivalent, it actually puts out 750 lumens of light and consumes 13 watts. Given the comparison to the bulbs from Home Depot, this seems more light an 85-watt equivalent. Either way, I like it. I'm happy.
Besides all of the energy saving features, LED light bulbs are great for recessed lights when you have an attic space above, because they generate far less heat, which means less heat gets transferred to your attic space during the winter, which can help to prevent ice dams. You can read more about that here - Recessed Lights are Evil.
Reuben Saltzman, Structure Tech Home Inspections
While most attic spaces in Minnesota are insulated with fiberglass or cellulose insulation, there is a relatively new product that provides superior performance: spray foam. On old one-and-one-half story houses, foam insulation can be an especially nice way to cut down on heat loss, air leakage, ice dams, yet maintain nearly the same headroom that already exists.
A popular way of re-insulating old one-and-one-half story homes in Minnesota is to have closed-cell (2 lb) spray foam applied directly to the roof sheathing, eliminating any ventilation. This type of spray foamed roof is commonly referred to as a 'hot roof'.
Why are they called 'hot roofs?' A traditional attic has an insulated floor and is ventilated. Outdoor air is allowed to come in through the soffits and leave at the top of the roof, creating a cold attic space during the winter. This helps to prevent ice dams, keeps the roof cooler in the summer which may help to prolong the life of the shingles, may help to prevent the accumulation of condensation, and satisfies the warranty requirements of the shingle manufacturer. When spray foam is applied directly to the roof sheathing, there is no longer an unconditioned attic space; the thermal envelope is moved right up against the underside of the roof. Because there is no longer ventilation, these are often called hot roofs.
Are they really hot? No, just slightly warmer. Studies have shown that color differences in shingles will actually have a larger impact on the temperature of shingles than the difference between a ventilated and a spray-foamed roof. A 'hot' roof will typically only be a couple of degrees warmer than a ventilated roof. This has the potential of reducing the shingle life by up to 10%.
What are the benefits? Closed-cell spray foam has a higher insulating value (R-Value) than anything else. Sprayed Polyurethane foam insulation has an R-Value of 6.8 per inch, while fiberglass batt insulation is about half that, and it's nearly impossible to install properly. Foam insulation makes for a perfect seal - no gaps, no air leakage, no attic bypasses. If ductwork is located in the attic space it won't need to be insulated, eliminating a lot of energy loss. Also, on old one-and-one-half story homes with no soffits or very short soffits, adding proper soffit ventilation can be difficult or impossible.
Are hot roofs allowed in Minnesota? This is a tricky question. The current version of the Minnesota State Building Code uses the 2006 International Residential Code, with amendments. If we turn to section R806.4, we find a section titled "Conditioned attic assemblies." This section says "Unvented conditioned attic assemblies (spaces between the ceiling joists of the top story and the roof rafters) are permitted under the following conditions:" ... and then goes on to list a bunch of conditions. So it would seem that hot roofs are allowed, as long as all of the requirements of R806.4 are met.
Not so fast though. One of the Minnesota amendments to the IRC, section 1309.0806, deletes section R806.4 in it's entirety. In other words, this says that hot roofs aren't recognized as an acceptable alternative.
Yeah but still... Minnesota Rules section 1300.0110 Subp. 13 says this:
The code is not intended to prevent the installation of any material or to prohibit any design or method of construction not specifically prescribed by the code, provided that any alternative has been approved. An alternative material, design, or method of construction shall be approved where the building official finds that the proposed design is satisfactory and complies with the intent of the code, and that the material, method, or work offered is, for the purpose intended, at least the equivalent of that prescribed in the code in quality, strength, effectiveness, fire resistance, durability, and safety. The details of any action granting approval of an alternate shall be recorded and entered in the files of the Department of Building Safety.
In other words, if a building official finds that an alternative method of construction is satisfactory and complies with the intent of the code (etc etc), they "shall" approve it. In February of 2011, a letter was written on this topic by Sr. Building Code Representative Donald Sivigny to State Building Officials in Minnesota, offering commentary on code acceptance of unvented attic assemblies. You can read the letter here - http://www.dli.mn.gov/CCLD/PDF/OpinionStaffAttic.pdf .
As mentioned in the letter, the 2012 version of the International Residential Code has expanded the section on unvented attics significantly, and they've also renumbered it as section R806.5. If you're curious about the differences, I put together a pdf showing the two code versions, which can be viewed here 2006 vs 2012 IRC on hot roofs. Keep in mind, the 2012 IRC has not been adopted yet in Minnesota, but I expect section R806.5 won't be deleted in the next wave of Minnesota Building Code changes, which are expected to happen in 2013. It will probably be changed in some fashion, however.
The way it stands now, some cities in Minnesota allow hot roofs as an alternative method of construction and some don't. I contacted the building inspections department in twenty of the largest cities in the Twin Cities area, to ask whether hot roofs, or 'unventilated roofs' were allowed. Here's a breakdown of what some of the different cities had to say about hot roofs. Not all of the cities responded.
No, we don't allow hot roofs.
Maybe. We might allow hot roofs if certain requirements are met.
For most of the cities that said they would entertain the idea of allowing a hot roof, they also said that they would only allow a hot roof if the shingle manufacturer's warranty wasn't voided by the lack of ventilation. For example, Owens Corning will not honor their warranty on asphalt shingles if a hot roof is used, but Certainteed does. By coincidence (?), Owens Corning does not make a closed-cell foam insulation product, but Certainteed does. Funny, huh?
The bottom line is that if you want to install closed-cell spray foam against your roof decking, you should check with your local building official and shingle manufacturer first.
Last week I received an email from a concerned reader who said his 85-year-old mother-in-law had recently purchased a $2,500 radiant barrier insulation system for her 1,800 sf townhouse in Austin, MN. She was convinced that this was a good investment after attending a free dinner, wherein the effectiveness of radiant barriers in Minnesota was highly exaggerated. The system was installed two days after she signed the contract.
Radiant barriers are essentially bubble wrap covered with foil on both sides. The material is sold in rolls, and is quite easy to install. The problem with this product is that it only works to prevent radiant heat transfer; it does nothing to prevent convective heat transfer, conductive heat transfer, or air leakage in attics. Can you guess how much heat is lost in Minnesota attics due to radiation? I'm no engineer, so I can't give you any hard numbers... but I know the answer is very close to nothing. In other words, the value of a radiant barrier in a Minnesota attic is very close to nothing.
I immediately wrote this concerned reader back, telling him this system was a waste of money. Two days after that email exchange, the Minnesota Department of Commerce issued a consumer alert warning about these types of insulation systems, saying the exact same thing. They're a waste of money.
Oak Ridge National Laboratory has concluded that radiant barriers will give an average Minnesota home some savings in energy - somewhere around $10 - $40 per year, assuming the home has ductwork in the attic. The problem with applying this generous savings model to Minnesota homes is that most Minnesota homes don't have ductwork in the attic. With no ductwork in the attic, the average annual savings would drop to about $5 per year.
If you want to improve the insulation in your attic, hire a reputable insulation contractor from Minnesota.
Have you ever noticed how snow will melt around the foundation on older houses? This will happen at any house with unheated foundation walls, and it's a great visual indication of how the house is losing heat. When there's no melted snow up against the house, we can rely on thermal imaging to figure out where the heat loss is occurring. In the image below it's right at the rim space; that's the part that shows up as the brightest orange / yellow.
While houses usually act like chimneys, sucking air in at the bottom and exhausting air through leaks at the top, the photo below is a perfect example showing how it doesn't always work that way. The frost that has accumulated against the siding is all coming from air that's leaking out of the un-insulated, un-sealed rim space. It was about -15 degrees outside when I took the photo below.
To cut down on basement heat loss, an obvious place to start at is the rim space. I mentioned this a couple weeks ago when I wrote my post about how I had my entire basement re-insulated, but today I'm going to focus on the rim space alone and discuss the different options for insulating and air sealing this space.
The old way of insulating rim joists was to use fiberglass batts. As I've mentioned many times in previous blogs, fiberglass batts are a poor choice of insulation for any project... but they should never be used at the rim space because it's nearly impossible to install a proper vapor barrier here, and fiberglass batts will allow for a lot of air leakage. Without a vapor barrier at the rim space, you'll have relatively warm, moist air passing through the fiberglass insulation and then condensing at the rim joist. This can create mold or rotting.
There are only two ways that I ever recommend to insulate the rim space: rigid foam or spray foam.
Using spray foam at the rim space is just about the only thing that is ever done on new construction houses in Minnesota today; while it's expensive, it's worth it because it can be applied quickly and does a perfect job of both insulating and air sealing the rim space. Wires, faucets, pipes... they're no match for spray foam. All of the penetrations get sealed.
While spray foam is supposed to be covered by an approved material to prevent the possible spread of a fire, the rim space is one exception to this rule; this exception can be found in the Minnesota Amendments to the IRC, section R314.5.11. Here in Minnesota, up to 5 1/2" of foam insulation can be sprayed at the rim space and left exposed. The only downside to using foam insulation is that it's relatively expensive. You can buy do-it-yourself insulation kits for fairly small jobs, such as a rim space, but I would personally just hire a professional to do this. It wouldn't cost much more than a spray foam insulation kit.
The alternative to having spray foam applied at the rim space is to install rigid foam insulation. Installing foam insulation at the rim space takes a long time, but it's not a very difficult project. Basically, pieces of rigid foam boards get cut to size, placed at the rim space, and caulked or foamed in place to help prevent air leakage.
While writing this post, I came across a great blog written by a handy homeowner, showing how he insulated his own rim space with rigid foam. You can view it here - rigid foam at rim space.
The one thing to remember when making a house tighter is that you'll have less air leaking in to and out of your house, which can create other problems, such as a backdrafting water heater or excessive moisture in the home. The Minnesota Department of Commerce Energy Information Center has a great handout that specifically addresses this topic, which you can download here - Combustion & Makeup Air.
If you don't have any insulation at your rim space, add this project to your list of 'to-do' projects. It's not as critical as attic insulation and it takes more time, but it's a good thing to do. Just don't use fiberglass.