DIY Network

Heating Up and Cooling Down, Pt. II: HVAC System Design From "Home IQ" episode DHIQ-119

In the first part of "Heating Up and Cooling Down" (DHIQ-109) you saw how the ductwork was fabricated and placed in the Oberg home, but in this final of two parts, it all gets tied together. See why controlling both temperature and humidity makes for a more comfortable home.

Being an architect, engineer and co-founder and chief technology office for IBACOS, Inc. (Integrated Building and Construction Solutions), a company out of Pittsburgh that enables the homebuilding industry to deliver quality homes of inherently higher performance that are safe, healthy, durable, comfortable and durable, Brad Oberg was interested in only the state-of-the-art technology when it came to his new home's heating-and-cooling system. This desire included being able to control the heating-and-cooling system (HVAC) from the touch of a button, which we'll discuss in detail later.

In DIY's new Home IQ series, you'll follow the Oberg family during the decision-making process of building this beautiful new home.

In this week's episode of Home IQ, we continue the process of equipping the Oberg home with a super efficient heating-and-cooling system.

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When it comes to comfort in a new home there's more to consider than plush furniture and conveniences, but also the air temperature and ventilation from room to room, which is the focus of this second of two episodes on the Oberg's HVAC system.

The HVAC has to be "carefully" designed for each home. The system that Brad (and his wife, Lynn) chose divides the house into two climate zones. Special machines called "energy recovery ventilators" (ERVs -- figure A) will control the fresh air in the house. Two fiberglass -- not metal -- trunk lines (figure B) are installed, and one will have the warm and cool air and the other line will be for the "return" air. These lines are created within the same ductwork, covered in episode DHIQ-109 (see the link in the first paragraph, above).

Figure A

Figure B

Figure C

Note: The warm and cold air trunk line feeds all the rooms with warm air or cold air, and the return trunk line takes the air out of rooms back to the furnace and conditions that air -- and these (figure C) long tubes go to each individual outlet.

	Figure D
	Figure E
	Figure F

Unique HVAC Feature in the Oberg Home

On-air Brad discusses a unique feature -- the locations of the supply registers -- of his home's HVAC system. "What's unique here is that the supply register (figure D) is actually quite high, it's above all the furniture so Lynn (his wife) doesn't have to worry about where she puts a chair or a table. The air can still get into the space."

Most houses, especially in a northern climate (outside Pittsburgh for the Oberg home), don't feature the supply registers so high up on the wall. Some information currently coming from building America programs and from mechanical engineers suggest that by placing the registers high on the wall you can get more "throw" of air in the room, which leads to a higher comfort level for the homeowners.

Note: Be sure to check out the link, below in Resources, for the U.S. Department of Energy's "Building America" program for more information on this topic.

The "return" register (figure E), however, is positioned low because it isn't as important for the throw (or flow) to be out of reach of furniture or other obstacles. In fact, the experts at IBACOS did research in their laboratory to prove this theory. A smoke room (figure F) was used to show how heat can be thrown across a room, down the opposite wall and ultimately around the room, which in turn provides better circulation than previously considered "conventional" practices.

	Figure G
	Figure H
	Figure I

Adding this innovative system isn't easy because the subcontractors have to learn "new" techniques for doing their jobs. Even the installation of ductwork is different. In fact, the Oberg's site supervisor, Greg Allen, said about the IBACOS system, "I'm not going to pretend to understand how it works. I know the basics. I know probably enough to be dangerous with the stuff, but I certainly couldn't duplicate the system without a lot of assistance."

At the heart of this advanced HVAC system is a "complex" mathematical calculation (figure G). The engineers have to figure out how much air each room needs, something they call the "load". They measure it in cubic feet per minute (CFM). They know that in each room an amount of air is needed to flow in to heat or cool the room to make it comfortable. From these air CFM volumes they can size the ductwork.

In order for the furnace to deliver the proper amount of CFMs, the system must have enough pressure to force the air "out" into the rooms. A combination of duct tape and Mastik is used (figure H) to keep all joints sealed tight, and with the smaller size ductwork with this new system, there will be more velocity and pressure. And this is why every "single" seam needs to be properly sealed.

Sometimes one duct will have more pressure than another, so a small damper (figure I) is put into each of these ducts, which in turn will give the homeowner total control where air-flow is concerned. The damper simply regulates the supply of air flow. This makes it easier to balance the system and flow of CFMs throughout the home. Each damper has a handle that can be turned open or closed, whichever the homeowner desires.

In the next segment find out how our homeowners monitor this new HVAC system with a computer and the touch of a button.

RESOURCES :

For more information on the topics contained within this article please reference The U.S. Department of Energy's (DOE's) Building America Program

The Building America program works with members of the home-building industry to produce quality homes that use less energy without costing more to build.

Website: www.eere.energy.gov/buildings/building_america/

Heat-N-Glo Fireplaces (Hearth & Home Technologies)
Hearth & Home Technoligies, Inc.
20802 Kensington Blvd.
Lakeville, MN 55044
Toll-free: 888-427-3973
E-mail: info@heatnglo.com or globalinfo@heatnglo.com
Website: www.heatnglo.com

Heating (White Heating)
White Heating
3467 Babcock Blvd.
Pittsburgh, PA 15237
Toll-free: 800-800-4328
Fax: 412-364-3632
E-mail: white@stargate.net
Website: www.whiteheating.com

Energy Recovery Ventilators and Air Conditioning (Carrier)
Carrier Corp.
7310 W. Morris St.
Indianapolis, IN 46231
Phone: 317-240-5219
Website: www.global.carrier.com

GUESTS :

Brad and Lynn Oberg
Homeowners
Company: IBACOS (Brad)
Title: Co-Founder/Chief Technology Officer
Website: www.ibacos.com

Greg Allen
Site Supervisor
Hendolhurst Homes
955 Markman Park Rd.
Baden, PA 15005
Phone: 724-935-5658
Fax: 724-935-0884
E-mail: gcrbs@adelphia.net

Anthony Grisolia
Building Performance Specialist
IBACOS, Inc.
Website: www.ibacos.com

Eric Newhouse
Systems Integration Designer
IBACOS
Website: www.ibacos.com

John Holton
Senior Architect
Ibacos
Website: www.ibacos.com

Gary Gressang
White Heating, Inc.
3467 Babcock Blvd.
Pittsburgh, PA 15237
Toll-free: 800-800-4328
Phone: 412-364-5003
Fax: 412-364-3632
E-mail: white@stargate.net
Website: www.whiteheating.com

Kevin Waldo
Product Manager
Carrier Corp.
7310 W. Morris St.
Indianapolis, IN 46231
Phone: 317-240-5219
E-mail: Kevin.waldo@carrier.com
Website: www.global.carrier.com

Jeff Thayer
Vice President, Sales
Hearth & Home Technologies™, Inc.
20802 Kensington Blvd.
Lakeville, MN 55044
Phone: 952-985-6577
Fax: 952-985-6777
E-mail: thayerj@hearthnhome.com
Website: www.hearthnhome.com