Comments on: Don’t Do HVAC to Me

By: Jamie

Jamie — Sun, 05 Aug 2012 19:02:40 +0000

We have had good luck with
We have had good luck with reversible geothermal chillers. Radiant floor heat with water dicoil air handlers, you just have to have a a/h you can slow the cfm way down to allow for dehumidification

By: Mike MacFarland

Mike MacFarland — Sun, 05 Aug 2012 08:27:07 +0000

Great summary, Allison. The
Great summary, Allison. The Northern California attendees of BSCamp especially loved Henry's acronyms:
KWH/M2/YRm= Energy Use/Yr (Measured) versus
KWH/M2/YRm= Energy Use/Yr (Modeled).
Did everyone catch the difference? Yep, out here in CA, they actually don't think there is any, either. We live in an imaginary state, so we might as well use the same acronym, right?

Oh and runner up was:
ATRst= Average Truth Ratio (solar thermal) and
ATRpv= Average Truth Ration (Photovoltaic)

Great talk, Henry. I'm the guy who asked you why you were wearing the Psych shirt, and where I can get one. I'm still hoping one shows up someday. :-)

By: Ted Kidd

Ted Kidd — Sat, 04 Aug 2012 02:36:18 +0000

LEED PP

LEED PP

Henry, you're awesome!!

By: John Poole

John Poole — Sat, 04 Aug 2012 01:34:22 +0000
Seriously, though: All my
Seriously, though: All my wise-assery aside, I thought this was an excellent article, and I'm intrigued by Henry's reasoning.

In planning my own solutions for updated HVAC systems in two single family homes of mine (cold climate), I'll be giving some serious thought to separating HVAC subsystems out, and see if it makes sense for my situation. Thanks!

By: moedaddy71

moedaddy71 — Fri, 03 Aug 2012 14:31:06 +0000

Hi Allison Bailes…was
Hi Allison Bailes…was wonder’n why the worry ’bout using crawl as return plenum?

By: Henry Gifford

Henry Gifford — Fri, 03 Aug 2012 09:42:38 +0000
Hi -

Hi -

Yes, I was specifically talking about large buildings, "large" meaning it is hard to avoid overheating or overcooling parts of the building, at least partly because the mechanical system gets very complicated as the building gets larger. But, I know of several single family homes, including some I have had some influence on, which have mini splits on the wall for cooling, or in the case of a high end brownstone mini splits hidden behind grills in the ceiling for cooling, and hot water to radiators for heating. Yes, thermost in each room. Yes, the mini splits could do heating also, but partly because of cheap gas and 25 cent electricity in NYC, and partly to avoid hot air heat, people pay for seperate heating and cooling. And, yes, a separate ventilation system. I also showed valences, which are baseboards upside down on the ceiling, which do both heating and cooling with water, and mentioned a 101 family building I am designing with mini splits for both heating and cooling, but that building will be very airtight and very well insulated, and low income, not luxury conditions, in which case the cost of another heating system might be justified.

Another way of radically simplifying things is to simplify the controls, because if you need all that fancy digital stuff, probably the mechanical stuff is also way too complicated to have a high chance of working, or working well for long. One great way to not need digital controls is to not do HVAC into combined systems - let the ventilation run 24 hours, or on/off or hi/lo on motion or CO2. (I usually do code minimum CFM, which means smaller and quieter and cheaper equipment, and requires 24 hour operation). After that, no more ducts, just Copper pipes for heating and cooling, usually heating by hot water, cooling by either cold water or by freon. Yeah, simple, cheap, easy, and zero square footage taken out of offices for fan rooms.

Henry Gifford

By: John Poole

John Poole — Fri, 03 Aug 2012 08:31:21 +0000
Give me a D (Deferential to
Give me a D (Deferential to historic import...)

Give me an E (Energy, of course...)

Give me an R (Reduction...the end result, not the treatment)

But don't do DER (Deep Energy Retrofit...or more precisely, the conventional work methods often used in achieving deep energy reductions) to me!

#OccupyDER

There. That's my cheer. Will you be sending me a psychrometric tee shirt? ;-)

By: Allison Bailes

Allison Bailes — Fri, 03 Aug 2012 06:11:57 +0000
Michael Blasnik<
Michael Blasnik: Yeah, that's my fault. I tried to give the context by discussing Henry's background in NYC apartment buildings, but I didn't tie that well enough to the Don't do HVAC to me theme. Once I'm done with the comments here, I'll go back and fix that in the article.

Lance: I haven't seen one posted yet, but John Brooks posted the link to the video of his earlier Summer Camp talk a few years ago: Henry Gifford 2008 Summer Camp video

Bradley: True. In new homes where you can make a really good enclosure, the heating & cooling can be greatly downsized, though, and that solves some of those problems.

John B.: I like your cheer! And thanks for the link to the video of his earlier talk, which I embedded above.

Bob G.: Yeah, I like mini-split heat pumps that can both heat and cool. With variable refrigerant flow, oversizing the cooling system isn't as big a deal because the capacity changes to meet the load.

Nate A.: Yes, I'll be writing about radiant cooling. I've been stewing on that one for a while. Good points about separating things out. As Michael pointed out, I didn't really give the proper context and it doesn't make as much sense for single-family homes. Cost-effectiveness is great for larger buildings, though.

Armando: I don't remember all the examples, but one was near an electrical box that gave off a lot of heat. One building had 3 t-stats right next to each other but serving 3 different parts of the building. Another was inside housing of baseboard radiator.

dave: Cost is very important for most of us, of course. In big, poorly performing buildings, there's a quick payback. In smaller buildings and single-family homes, maybe not.

M. Johnson: Thermostats in every room is for homes/buildings with boilers and hydronic distribution. Sorry, I should've had that in the article. The radical simplicity refers to Henry's looking at how things are in buildings and trying to figure out the best way to get them where they need to be.

Thomas A.: Great point, and the kind of stuff Henry does.

moedaddy71: Glad that works for you, but I'd worry about using the crawl space as a return plenum.

David B.: Sorry, as I said to M. Johnson above, Henry was talking about large buildings with boilers and hydronic distribution.

By: David Butler

David Butler — Fri, 03 Aug 2012 03:48:21 +0000
"If you don't have a
"If you don't have a thermostat in every room, you're not even in the ballgame"

Easy to say... (especially when in cooling dominated climates)

Michael B wrote:
> I think everyone is misinterpreting the talk. Henry was not talking about single family homes -- he was talking about multifamily and small commercial buildings.

Thanks for clarifying.

By: moedaddy71

moedaddy71 — Fri, 03 Aug 2012 01:34:33 +0000

I built my own place in ’85,
I built my own place in ’85, 2050 sq ft, single story ranch, “S” side faces Ohio River so for pan view, lots of dble-pane glass doors, full length windows, hi ceilings, 2X6 walls, attic FG batts + blo ins. I just knew, intuitively that ducts in attic was out, vented crawl was out. HVAC in gar was out, ht pmps out, any open flame in gar out. So…the crawl is concrete floor, also used as return plenum , HVAC in crawl, hi E cond furn,bills always lower than comparable ftage, added on ’04, now have 3500 sq ft, 2 furns in crawl, 2 AC’s, mo hi ceilings, 3 stats, still do’n betta anybody, I’m so dang smart it hurts my big head to hear the piddly stuff. moedad71, call me!