Letters: November/December 2006
A version of this article appears in the November/December 2006 issue of Home Energy Magazine.
I live in Hereford, Arizona, which is a small town next to Sierra Vista, which is a larger town north of Bisbee, Arizona. I am pretty close to the Mexican border.
The climate zone is high desert here—we’re over a mile above sea level; however, I live in the mouth of a canyon, so my weather is a little colder and windier than the weather in town—which is fine in the summer, but not so fine in the winter.
My double-wide is old and drafty, which is why I am looking for some material that I can board up the windows with during the winter, but that looks okay and doesn’t require a lot of effort. The plastic stuff I used last year worked, but was difficult to put up and didn't look very good, to say the least. I felt like I was living in a fishbowl all winter!
I was wondering if there is a foam that comes in blocks or something that I could cut to fit around the inside of the windows, since this is where the air comes in, around the frame.
Thanks for any help you can give me.
Author and residential energy expert Cal L. Steiner replies:
I would suggest the old-fashioned clip-on interior storms with the aluminum flange. Cheap and effective. They will need to be removed every year and stored; or you can leave them on the windows you do not need for summer ventilation. I would also suggest that you caulk around the interior casing so there is no air bypassing the storm. Also consider attaching some thin open-cell foam with adhesive to the flange of the storm for a better seal. Other than that, the 3M shrink-wrap works great, especially on windows that will be left on all year and will not be opened during the summer.
If, in your opinion, you have more windows than you need, you should consider eliminating them by framing out and insulating them.
I’ve seen some folks take 1/2–1 1/2 inches of foam, cut it to fit, and cover it with a cloth material. This is then put in between the window and the screen.
This is taking into account that you live in a fairly cold winter climate.
Is Rightsizing Wrong?
With the 2006 Energy Star “rightsizing” HVAC sizing requirement that went into effect on July 1, 2006, energy raters all over the country are beginning to tell builders that their HVAC contractors must downsize their systems to within a 15% oversize in order for the house to qualify for the Energy Star program. This will be putting raters, especially small raters with no engineers or licensed HVAC professionals on staff, in a very difficult position, with no apparent support from the industry on how to correctly handle the situations that will inevitably arise with our customers. In addition to this, there seem to be serious oversights in the technical specifications of the “rightsizing” rule.
Meetings between the builder, rater, and HVAC contractor will occur at which the HVAC contactor will bring a load calculation that (most likely) has been incorrectly performed. Regardless of the rater’s level of knowledge regarding load calculations, in my experience, the contractor will not understand or believe the rater’s arguments on load calculation details. In the end, the HVAC contractor will ask the rater if he or she has an HVAC license and/or has an engineering (PE) stamp. If the rater answers no, the HVAC contractor will tell the rater that he or she cannot legally take responsibility for the HVAC contractor’s system. That is—as the one who holds the HVAC license for this job—even if the builder tells the contractor to follow the rater's advice, the HVAC contractor is not legally able to transfer that responsibility to the rater or anyone else. What should the rater do at this point?
Some HVAC contractors will be willing to attempt to transfer that responsibility anyway, with release let ters. In this case, the contractor will ask the rater if he or she is willing to take responsibility for system/duct replacement should there be problems with the sizing. Since no industry letter exists for raters to take legal responsibility for the sizing, they will be forced to create their own letter to give to the builder. The HVAC contractor will also create a similar letter to give to the builder (the last one of these I saw read that the HVAC contractor “would not be responsible for any issues should the HVAC system not perform as the home owner might expect”).
Whether it’s actually legal or not, if raters are specifying equipment sizing, they are accepting responsibility for the system sizing. Many raters will be taking this responsibility with little or no training on how a proper load calculation is performed, or how to correctly review a load calculation. (Whether that can even be done without just doing the load calc over is something I question.) Training facilities such as Southface Energy Institute in Atlanta, Georgia, only give brief mention of load calculation issues in their HERS rater training.
What happens when, for whatever reason, the systems are found to be undersized and equipment/ducts need to be replaced? Will raters take responsibility for a load calc they didn’t perform? Will HVAC contractors take responsibility for system sizing they didn’t agree with? Amazingly, there seems to be no contingency plan from RESNET or EPA for this inevitable situation. By ignoring the implications of this question, EPA and RESNET are putting small raters in a situation that may very well threaten their very ability to stay in business!
Despite my repeated requests that the EPA/RESNET formulate a plan or some sort of support structure for the raters to address this situation, there has been no action on their part to address how the small rating companies without engineers or licensed HVAC professionals on staff will handle this. Perhaps this is because the people in the position to address this issue are not actually raters, or they are raters who do have engineers and/or licensed HVAC professionals on staff.
Those raters without the above-mentioned engineering or HVAC qualifications know that this situation is about to occur because we’ve already been dealing with it.
The situations described above are from actual events and echoed by other raters I have communicated with. We have been circulating HVAC load guarantee letters among ourselves, which I created in my office! It’s a sad state of affairs when we are using a self-created letter as some kind of quasi-legal document for a situation in which we’re not entirely sure where the legal boundaries are in the first place! Sure, we could individually or collectively hire lawyers to help us with a letter and do more research to try and determine the legality of the situation, but I think I can speak for my fellow small-business owners when I say we are running as fast as we can to keep up with our own businesses.
Beyond these bigger-picture issues, there are also real-world technical issues with the coming Energy Star equipment sizing rules that also don’t seem to have been considered. Unlike the thermal bypass checklist that has been provided to help raters to correctly perform framing/insulation inspections, there is no information regarding how raters should correctly evaluate a load calculation. Issues like sealed crawlspaces, sealed attics, duct locations, orientation, and so on have a very real impact on load sizing. Another seemingly glaring oversight is that EPA specifies that the HVAC sizing must be within 15% of total load. No mention is made of the sensible/latent load split. It would be easy to undersize the sensible or latent load while adhering to the total size limitation. There is also the issue of 1.5-ton systems being the smallest available, and even that size being more than 15% oversized for smaller efficient homes, or for separate floors on larger homes.
These are just a few of the many technical reasons why the “rightsizing” rule is not going to work in the real world. Why is it that our industry leaders at EPA and RESNET do not recognize this situation for what it is? It astounds me that, despite vigorous opposition, such a flawed approach to a technical standard has managed to make its way into the Energy Star program, and that the RESNET organization’s response to this serious issue has been so lacking. While members of the RESNET technical committee board have told me that they strongly disagree with EPA’s “rightsizing” rule, and repeatedly attempted to get EPA to modify or eliminate it, this doesn’t explain why they have done nothing to support small raters with the situation we now find ourselves in.
Building Performance Specialists
Wilmington, North Carolina
David Butler, an HVAC engineer and ASHRAE member who works for Environmental Building Solutions in Charlotte, North Carolina, is also very concerned about the new rules. Here's what he has to say:
I see three problems with the new Energy Star rules on verifying air conditioning sizing:
1. Unless the load was done in-house, there’s no way to verify that a load calculation is correct. The checkoffs specified in the Energy Star rules only scratch the surface.
2. The new rule will make it easy for mechanical contractors to point the finger, shifting liability to the rater whenever possible. This is especially troublesome since most comfort complaints (for example, high statics, improper room-to-room air flow, excessive duct leakage, improper charge, and so on) have nothing to do with sizing.
3. Sizing HVAC equipment is not a trivial exercise. In fact, many mechanical contractors are not properly trained for this and simply substitute additional equipment capacity for sound procedure.
Given an air conditioner of a particular nominal tonnage, the sensible (and even total) capacity can vary greatly from one manufacturer to another and from one system to another, depending on coil selection, air flow, and design conditions (especially entering dry bulb and wet bulb). Unfortunately, ARI ratings are the only readily available source of equipment data, and they don't include sensible capacity or sensible ratio. Moreover, ARI ratings are based on design conditions that don't match reality. For example, ARI ratings are based on 80≈F indoor dry bulb, while the new Energy Star sizing rules require the load calculation to be based on 75≈F. In other words, ARI data should never be used for equipment sizing!
The new Energy Star rules refer to ACCA Manual S: Sizing, which addresses these issues in depth and describes the proper procedure for sizing. But this procedure requires access to comprehensive engineering data from the manufacturer, data that consider the impact of air flow and coil selection at various design conditions. However, these data are very difficult for anyone other than dealers to obtain and interpret.
Many mechanical contractors are unaware of Manual S and rely solely on ARI data for sizing decisions. They avoid undersizing by assuming worst-case for windows, infiltration, duct leakage, and so on, and then round up at every opportunity. Even those who do a careful load analysis will often add another 1/2 ton or more “just to be safe”! There’s simply no incentive to do otherwise.
If raters do the “right thing” in good faith without technical training, many will ultimately hurt some homeowners, exposing themselves to liability. If it is not addressed by RESNET, this situation will eventually create a black eye for the home performance industry.
Despite everyone's good intentions, the folks who wrote the new Energy Star rules on equipment sizing apparently didn't consider the legal and technical challenges of having untrained raters verify proper air conditioner sizing.
Sam Rashkin, the national director of Energy Star for Homes, replies:
Rightsizing is an important component in building an energy-efficient, comfortable home. By including rightsizing in the new Energy Star guidelines, EPA hopes to accomplish two goals—to raise awareness of the value of rightsizing and to provide an initial level of verification that sizing calculations have been done.
Where rightsizing has been performed, typically the analysis has been the responsibility of engineering consultants or HVAC contractors installing systems for builders. However, the range of value-added services offered by HERS providers and raters is expanding, and could include performing load calculations and determining proper equipment sizing. Thus EPA feels that builders should have a choice in deciding who is responsible for these activities.
EPA does not require formal documentation of detailed sizing calculations to show that this requirement has been met. Where someone other than the HERS provider and/or rater is providing the rightsizing analysis, it is up to the HERS provider and/or rater to verify that the calculations have been performed for the specific home or model being rated and that the builder accepts responsibility for compliance with rightsizing procedures specified in EPA's guideline notes. The HERS provider and/or rater may verify that the rightsizing has been performed by requesting a sample load calculation to observe it has been performed, but is not required to check the accuracy of all calculations. The HERS provider and/or rater may also verify that required procedures have been followed by asking verbally or in writing for the builder to confirm that their consultant’s or HVAC contractor’s practices meet EPA requirements. If the HERS rater has performed the rightsizing analysis, then he or she is responsible for the calculations and adherence to EPA specified procedures.
In light of requests for clarification on rightsizing verification, EPA will review the rightsizing requirement language in the guidelines and make edits as needed.
Mysterious White Flakes
We are on well water and needed to replace the magnesium anode rod in our electric water heater tank with an aluminum-zinc anode rod. My plumber mistakenly put both magnesium and aluminum anode rods in the tank. By the time we found out, several weeks had passed. We removed the magnesium rod and had to chlorinate the tank because of the smell. We are now getting what looks like white sediment floating in the water, and when it settles it looks like white plastic. Our refrigerator seems to be hooked up to the hot water supply, because when our ice cubes melt we see the same sediment. We also have a smell when the ice cubes melt, but not when they are frozen. Any idea what is in the water and how to get rid of it? Could both rods being in the tank at the same time have caused a chemical reaction? Could there be a problem with the dipstick?
Water heater expert Larry Weingarten replies:
I think there are a couple of different things going on here. The aluminum-zinc rod you mention is specifically made for odor. It is often but not always effective.
It is not helpful to use more than one anode material in a tank. The magnesium rod will get eaten away to protect both the tank and the aluminum anode. You should have only one aluminum-zinc anode in the tank, unless it is about 75 gallons or more. This will protect the tank while reducing the possibility of too much hydrogen gas being generated in the tank. Hydrogen “fuels” the odor problem.
The floating white bits may actually be from a decomposing dip tube. If the bits are all of uniform thickness and angular, they are probably old dip tube; very little else floats. You don't mention the age of the heater, but dip tubes were a problem not long ago. Flushing the tank after replacing the dip tube will help, but it may not entirely take care of the problem, particularly if much of the old dip tube has fallen into the tank.
In the September/October 2006 issue, the article “DOE Announces a Third Reflector CFL Winner,” p. 45,
contained some information that was dated or incorrect. Here is the most current information:
“The Feit reflector compact fluorescent lamp can be purchased at volume discount pricing in quantities as few as four lamps. The R-CFL Web site (www.pnl.gov/r-lamps) provides details, including purchasing information, on all winning R-CFL models. The Web site will soon post information on new R-CFLs that have passed testing for high-heat applications.”
In the article “Cool Roofs Cool the Planet,” on p. 40, the vertical axis on Figure B shows numbers that are off by a factor of 10. In the figure, 5≈C should be 50≈C, and so on.
In the article “Market Changes,” Table 1 (p. 31) was incorrectly reproduced. The correct table is
shown to the right.