It’s been a tense couple of weeks for Greenspiration.
I thought the whole closed cell versus open cell foam insulation topic was controversial but that was nothing compared to the sizing of the geothermal unit that will go in my Greenspiration home. I have this little issue to thank for the fact that we are now officially 3 weeks behind schedule.
As recently as a few days ago, I was trying to come to terms with how I could possibly be building a home with geothermal heating and cooling….high-end foam polyurethane insulation….a closed crawl space….low – e windows….Energy Star appliances….solar tube lighting….advanced framing techniques, ( etc., etc., etc) and still not qualify for Energy Star certification! If you too are wondering how my deep green home could be struggling over the fence of what many consider to be the minimum green building standard out there, then perhaps you will appreciate my frustration.
It all came down to the sizing of the geothermal unit. In a nutshell, my HVAC contractor thought I needed a 4-ton system while the Energy Star rater thought I would be fine with a 3-ton system. Both had run their calculations, each using their own Manual J “equivalent” software. The Energy Star rater came up with a cooling load between 2 and 3 tons. The HVAC contractor came up with a load just over 3 tons—and was not comfortable guaranteeing a 3-ton system. Energy Star allows for 15% over-sizing of an HVAC unit OR the next size available in a chosen product line. In our case, this was the EnvisionTM Series geothermal system by WaterFurnace, which like many hvac units, is not available in half sizes. Just my luck.
3 tons, 4 tons…. I really didn’t care. Like any other homeowner, I just wanted a system that would work efficiently. I wanted a HVAC contractor who was willing to back up the system he installed. And I wanted my Energy Star certification. I didn’t much want to get into a sizing battle, and didn’t really feel I deserved to be put into that position, but there I was.
Here’s the dilemma. Although both the Energy Star rater and the contractor concurred that my house was in the general neighborhood of needing a 3-ton system, the HVAC contractor could not shake the overriding fear that on a very hot day my shiny new geothermal system--for which I had paid handsomely--might not keep up with my demand for cooling. He knew as well as I did who I would call if my HVAC system wasn’t keeping me cool. HIM.
To be perfectly candid, it’s a very tricky area. As a writer for the commercial HVAC industry, I’m well aware that systems are very often oversized, and that this can cause a lot of problems, not to mention something that I hate, which is WASTE. At the same time, the 4-ton unit that my contractor had specified was a 2-stage unit, meaning that it would operate at low speed most of the time—so typically it would not operate as an oversized unit.
A Tough Decision
Since neither party was budging from their stance, I consulted with another mechanical contractor who used his own software to do his own load calculations. His numbers came up just above the Energy Star rater’s. Still, when asked if he would advocate a 3-ton or a 4-ton system, he agreed with my own contractor – that the 4-ton system would be preferred. He based his recommendations on the fact that the 4-ton unit is a 2-stage unit that would operate at first stage most of the time and also his concern that a 3-ton unit would be borderline on very hot days.
Even with two contractors’ recommendations, I was prepared to insist on a 3-ton system if a second Energy Star rater agreed that that’s what I had to have to get my rating, even though it would mean signing an agreement to my HVAC contractor that I would not scream at him (or hold him responsible) for selling me a system that couldn’t keep me cool on a 95 degree day. As a homeowner it was an unenviable position, and quite frankly one that I resented being put in, but what were my choices? To make a long story short, we consulted with a second Energy Star rater WHO SAID….
….It could go either way.
It was an anti-climactic end to a situation that had us all tied in knots for weeks. I write about it here because it’s a fairly common situation. As yet another Energy Star rater in another part of the country wrote to me, this is when the homeowner has to play the part of an “arbitrator”. But speaking as a homeowner striving to do her best to build a green home, I don’t like being put in that position. But it is what it is. That’s the extent of my whining—although I do look forward to exploring this subject in an article I am writing for an HVAC contracting publication.
You Gotta Smile
We are installing a 4-ton 2-stage WaterFurnace EnvisionTM Series geothermal system. As I write this, my HVAC contractor is delighted to at last be installing equipment and not crunching numbers, sharing numbers, or talking on the phone with engineers. I visited the jobsite today to check his progress. It was an unusually balmy day, with breezes streaming in through the open windows of my newly framed home.
“You know, it’s pretty cool in here today,” I said. “I think maybe I don’t need a hvac system after all.”
The contractor was busy dragging great lengths of silvery flex duct around like a giant anaconda. He didn’t bother looking up at me as he said, simply, “Yeah, Trish. I wouldn’t buy one.”
They don’t give LEED points for sardonic wit but I’m thinking that perhaps they should. A sense of humor is surely a pre-requisite for any home construction project that doesn’t end up killing you or breaking your spirit. I continue to be grateful for the patience, “sticktoittiveness,” and wit of my builder and contractors on this challenging project.
One final note: One other issue that factored into our decision to install a 4-ton system was the bonus room above the garage. We had planned to leave this large space unfinished for the time being simply for budgetary reasons, realizing that at some point we will completely finish it. With the 4-ton system we will have plenty of cooling capacity for this room. This may or may not be something an Energy Star rater is willing to take into consideration, but as a homeowner who has opted to invest in a high end geothermal system, it’s nice to know that my home won’t require auxiliary heating or cooling when we decide to “fill it out” a bit more.
Ode to the Great Seamstresses of World - Journal Entry - 02/28/09
Sleuthing the Noise in Our Ventilation - Journal Entry - 02/27/09
My Greenspiration Valentine - Journal Entry - 02/19/09
"SEAMED" Like a Good Idea at the Time: - Journal Entry - 01/20/09
Floors to "DYE" For. - Journal Entry - 01/15/09
A Funny Story about Our Kitchen Lighting…. - Journal Entry - 01/05/09
Happy New Year Greenspiration Voyeurs! - Journal Entry - 01/01/09
I.O.U. Journal Entries! - Journal Entry - 12/18/08
If Walls Could Talk, These Would Say, “I look MAVALOUS!”- Journal Entry - 11/27/08
Woulda, Coulda, Shoulda- Journal Entry - 11/22/08
Name that Geothermal Unit!- Journal Entry - 10/24/08
This part of the construction process goes fast. - Journal Entry - 10/19/08
Okay, so we’re finally registered for LEED-H - Journal Entry - 10/08/08
"It was the best of times, it was the worst of times..." - Jounal Entry - 09/16/08
It’s been a tense couple of weeks for Greenspiration. - Journal Entry - 08/11/08
A lot can happen in a couple of weeks. - Journal Entry - 07/04/08
Groundbreaking: A Tree Leans On Greenspiration - Journal Entry - 05/31/08
"How's the house coming, Trish?" - Journal Entry - 03/31/08
