Attending a week long class where veteran trainer Rick Chitwood is moderator has been entertaining and joyful. In the class which is inside a house that is being retrofit completely we are now designing and installing a super efficient HVAC system.


There are about 12 students at this class, from energy auditors to HVAC technicians. We are all in it toghether. We are three days into the 5 day class. 

This is all new ducts, all new registers, all new ... well everything. The house had a package gas heat AC system on it to begin with. Now we are installing a split heat pump. The old system was a 3 ton. This new one is about 1.4 tons because we are setting it to run on low stage only and never second stage. The airflow for the ducts is designed for low stage only.

 

A properly designed duct system is easier than making whip cream pie.

 

The house used to have about 9 supply grilles and now we have about 5 supply grilles. It is so much easier to install half the grilles and half the ducts as compared to the older system. I have some good footage that I will incorporate into some video training eventually.

 

  • "After installing systems this way, it makes one wonder why it would be done otherwise."

 

----

There is another one of these classes being done next week. I will be documenting the next class even more. That house coming up will have only three supply registers for the entire house. The house next week I will be video documenting for the Super Efficent HVAC series.

Stay tuned. Connect with the "Super Efficient HVAC Series."

Fill out the "Get UpSmart" form on the UpSmart Home Page and mention the series above, and well give you access to "Home Performance Best Practices Manual" that is full with resourses on energy audit tips and HVAC sizing and design strategies.

 

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Tags: AC, Efficient, HVAC

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Comment by Christopher Cadwell on January 15, 2012 at 9:38pm

You have to use judgement on reducing quantity of registers. If the entire duct system is going to be replaced, then use as few as possible. 

If you are pushing the limits on the sizing of equipment it is also important that the registers and grills chosen mix the air, or this could cause stratification issues.

If the retrofit is mostly equipment changes, with only moderate downsizing, and the ducts are just being modified with some sealing, and a little replacement, then the register quantity and sizing becomes less important. 

Comment by Bob Blanchette on January 14, 2012 at 8:13pm

I've been looking into reducing duct/register count in my own home. With 3 bedrooms and 1 large living/dining/kitchen area I don't see how this could be done with less than 4 registers. Currently there are 2 registers in the living room and 1 in the kitchen/dining. Each bedroom has one register. I've already eliminated the registers in the  bathrooms/closets/utility room. Bathrooms have 1,500W wall heaters. The house has 2 20x20 returns on for each side of the house. 3 ton A/C and 88,000 BTU furnace in a 1600 sq ft house. Furnaces is a about twice what it needs to be, and a 2 ton A/C would be plenty.

How much of a difference does it really make to eliminate all the extra registers and the associated ductwork?

Comment by Christopher Cadwell on December 5, 2011 at 12:11pm

Sorry I was not getting the latest comments.

Yes Carlos has it right. Then nearest thing is on his link. http://www.thinkenergystar.com/event/renoconference/building-and-re...

There are no upcoming live classes where the units are installed over a weeks time just yet, and I was asking for links to the landing pages. The administrators have not set times for future classes yet. I will post here when they do.

Comment by Carlos Espinoza on December 3, 2011 at 7:23am

Judi: Rick will be teaching, though not hands on, at the High Performance Home and Commercial Building Seminar starting this Monday, Dec. 5th.

http://www.thinkenergystar.com/event/renoconference/building-and-re...

Comment by Christopher Cadwell on December 1, 2011 at 3:37pm

"The only downside I can see is setting to a lower temperature and do not program a return time because your not sure or don't have a progammable. On returning it will take longer to reach higher temperature."

 

Are you talking about when you go on vacation for a couple of days? 

 

Otherwise these systems in cooling only use about the same watts use as a blow dryer, to keep the house 72-75 degrees. There is no need for a programmable thermostat in that case - you just set the temperature and leave it there - be greedy for comfort.

 

They do have a longer recovery time if you let the temperature droop I suppose. I have never had a customer complain about it.

Comment by Leo Klisch on December 1, 2011 at 11:35am

The only downside I can see is setting to a lower temperature and do not program a return time because your not sure or don't have a progammable. On returning it will take longer to reach higher temperature.

Lee

Comment by Christopher Cadwell on December 1, 2011 at 10:12am

The live class was recently done in Las Vegas at a home there. 

 

"What process was used to determine where to put the grilles/diffusers?  Was air mixing a concern with a the lowered heating capacity?  Were all of the ducts replaced, or were some of the former ducts used?  How did they determine what size duct to use?"

 

-- These questions are the essence of the class. We replaced all the ducts of course. But the latest house we did which is about 1400 sa ft only has 3 supply registers. It is very important to use the correct registers in that type if install to ensure the air in the house properly mixes. It is not hard to select the correct grille for this.

 

I see you both signed up for the series. I will address proper grill selection as one of the first segments.

 

Thanks.

Comment by Wes Davis on December 1, 2011 at 8:43am

Christopher,

Super efficiency is certainly a GREAT value and it is always easier to do it right than to do it wrong over and over and over.  I am curious just how easy it was to do the Super Efficient HVAC the way Mr. Chitwood explained it.

What process was used to determine where to put the grilles/diffusers?  Was air mixing a concern with a the lowered heating capacity?  Were all of the ducts replaced, or were some of the former ducts used?  How did they determine what size duct to use? 

Thanks,

Wes

Comment by Judi Lyall on December 1, 2011 at 8:08am

Hi Christopher,

    Will you share where you took this class, I would be interested in attending a class of his.

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