Clear Answers to Homebuilder Questions
In a webinar led by Ari Rapport, a Building Performance Specialist with IBACOS, we looked at ENERGY STAR® Version 3 from a homebuilder’s perspective. Ari was joined by Anthony Grisolia, IBACOS' Services Manager, and Sam Rashkin of the EPA, the National Director of ENERGY STAR for Homes.
This webinar generated many good questions, and so this is the second of two articles on the Q&A that came out of that session. The webinar dealt with the relationship between ENERGY STAR® and the evolution of codes, how to use ENERGY STAR’s Performance Path to your advantage, and the most confusing conditions of the program and how to address them.
How are two-stage compressor heat pumps handled by the ENERGY STAR program?
[Ari] I think that as long as the equipment meets the loads and design according to the checklist—and
you’re asking specifically about oversizing questions—I think that if your equipment is going to run at a two-ton level, and your load is calculated to that, then a two-stage compressor would be fine.
[Sam] We deferred to ACER, who developed the quality installation standard, on that concern, and 
essentially the feedback is that it applies to all equipment. So the answer is, especially from a sizing perspective, is that it still applies.
The only issue is that with variable speed equipment, you cannot use the air handler fan for a supply-only ventilation system. And we made an exception for variable speed systems. For a supply-only system with a recycler, you’re not required to use a variable speed unit. So where variable speed came up as an issue was the requirement was that it had to be variable speed if you had ventilation system that was a supply-only system. The exemption came up with the recycler controller, you don’t need to be variable speed. In terms of sizing there is no exemption.
(Referring to “Residential State Energy Code Status,” Slide 11) Those dark states that already adopted 2009 IECC (International Energy Conservation Code), do you see those states as being more open in adopting ENERGY STAR?
[Sam] Yes and no. There are some states that are not as dark, like Texas, where we expect to have a lot of success. Arizona, a lot of success, it’s not even any shade of blue, so there’s variations. But I would say that the states that are the darkest are definitely going to be strong players, although one there, Pennsylvania, is coming in kind of late, Maine’s kind of a slow player, Iowa has been around for a while, Montana’s kind of new. It’s kind of mix and match a little bit. And then you have some states that are dark that even have codes above the IECC, California, Oregon, Washington and Florid and they’re actually adopting new reference designs for those states.
Did ENERGY STAR Version 2 have any HVAC checkpoints?
(Ari) There were a few checkpoints in the Version 2 program and those were around the verification of rightsizing for HVAC equipment. And those were significant in their time, there was a lot of discussion and movement in the industry around those requirements for ENERGY STAR, but the HVAC system checklists for Version 3 are significantly more comprehensive than Version 2.
As a builder, they may have a specific set of plans, but sometimes they have a lot of options. What if the option is an additional bedroom? How do they deal with that?
[Ari] Sam, correct me if I’m wrong, but what that would be doing, is adding an additional bedroom, and probably, assuming that the square footage didn’t increase dramatically with the new bedroom, it might allow the builder to fall under the benchmark.
So it’s specific to that plan, that lot?
[Ari] Exactly.
[Sam] The bigger question that’s come up that I’ve had to reply to several times is, what if I have a specific size floor plan, like 4,000 sq. feet, and sometimes it’s four bedrooms, and sometimes it’s two bedrooms, because I have a buyer who wants an office instead of a bedroom or a playroom instead of a bedroom. And my response has been this, and I hope this is received well, it’s that, the idea here is not to be too punishing to the industry. If you’re a production builder building a house and a room could be used as a bedroom or an office, we think it’s fair to say that room is a bedroom slash office. It’s likely the first buyer obviously wanted the office, so you reassigned a room from a bedroom to an office, but it’s not to say the next buyer moving would not go back and use it as a bedroom. As long as there’s a place or in fact a closet allocated for that room and it has the window size required for the resident definition, that could be either a bedroom or an office.
So you don’t want to make it crazy for a builder with one size model that can be reconfigured with a bedroom or an office, to have to come up with a multitude of different HERS scores. So just to be clear how we address that: If you can assign a room to be either a bedroom or an office, that means that it will yield a consistent set of requirements for the ENERGY STAR label.
I know bringing ducts into conditioned space helps the HERS score. On average, how much does it reduce the HERS score? Any idea? Five points?
[Ari] I think it depends on the climate zone that you’re in, but it is a significant reduction.
[Sam] Yeah, particularly if you’re in a situation where you need points for a home bigger than the [ENERGY STAR] benchmark home, that’s a great strategy.
Ari Rapport, Sam Rashkin, and Anthony Grisolia Discuss ENERGY STAR Version 3
