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This Article Is About Variable-Speed & Zoned HVAC.  Al’s Plumbing, Heating & A/C, in Plano, Texas provides full service plumbing maintenance, repairs and replacements for every plumbing component in your home.  Al’s sells and installs Rheem Professional Series gas & electric water heaters, and tankless water heaters.  Al’s Plumbing, Heating & A/C is near your home in Plano, Allen, and Frisco.  We service all homes in southern Collin and Denton Counties with no additional travel charge.

Al’s also provides maintenance & repairs for all brands of Central A/C, Gas & Electric Furnace, and Heat Pumps.  Additionally, we sell and install new HVAC Systems from American Standard (same company as Trane), Ameristar (same company as American Standard) and Coleman HVAC (same company as York HVAC).

Variable-Speed & Zoned HVAC

photo of new home

Image Source: Pixabay.com

An Upgraded, Variable-Speed & Zoned HVAC System Can Keep A Two-Story Home The Same Temperature Upstairs & Downstairs. 

Your existing HVAC System may be working exactly as it should, yet not meeting your needs.  This is often due to areas in the home that are too warm & other areas that are too cold.   This is a naturally occurring problem in two-story homes.  Since heat rises, the upper level will always be warmer than the ground level.  Add DFW’s blazing summer sun & heat, and you have an upstairs that is often notably warmer than the first floor.

In single HVAC System homes, occupants often partially or completely close air ducts in some rooms to keep additional heating / cooling from being added each time the HVAC System runs.  While this is ok with 1-2 air ducts, closing more causes problems with the HVAC System.

Closing several ducts causes too much pressure inside the ductwork.  The HVAC System was designed and installed to operate with all ducts fully open.  If you close several ducts, the same volume of air is being moved (by the furnace blower) but there is no where for some of the air to go (due to closed ducts).  This creates excess pressure inside the ductwork, and the System cannot run as it was intended to.

two central air conditioner outdoor units

Image Source: Dreamstime.com

Most Larger Homes With Zoned HVAC Have 2 Or More HVAC Systems.

 

Details About; Single-Speed, Variable-Speed, and Variable-Speed & Zoned HVAC Systems. 

Most HVAC Systems are Single-Speed.  It’s either on or it’s off.  When on, it’s running at top speed.

A Single-Speed HVAC System is not designed to be a zoned system.   Since the System can only run at one speed, closing off vents or ductwork does little more than create a build up of pressure inside the ductwork.  This causes too much air coming out of the ducts that are open.

  • This makes the room cool or heat too quickly, which makes it uncomfortable.
  • Air coming from open ducts will make much more noise, due the excess volume of air.
  • Since most ductwork has some leakage, more pressure = more leakage.  It’s common when people close several air vents, often the see little or no reduction in cooling & heating costs.

A Basic Variable-Speed HVAC System is not designed to be a zoned system.  This system adjusts the HVAC System’s output to match the amount of cooling or heating that is needed at the time for the entire house.  As cooling / heating demand rises, the System speeds up.  As cooling / heating demand lowers, the System slows down.

A Basic Variable-Speed HVAC System is designed to operate with all air ducts fully open (just like a single-speed System).   If ductwork zones are closed off, the blower-fan will speed up instead of slow down (to counteract increased pressure in the ductwork).  This will cause the open ductwork to make more noise and move too much air, reducing comfort in open zones.

 

With An Upgraded, Variable Speed Zoned HVAC System, The; Electric Dampers, Furnace Blower-Fan, Furnace, & A/C Are All Controlled By One Control Board.  

The control board sends a message to the Zoned HVAC System to speed up or slow down based on how many zones that are open.  The control board is programmed to know the amount of airflow required for each zone.  This allows it to tell the System how much to speed up or slow down based on the number of open zones.

Upgraded, sophisticated HVAC Systems will likely benefit from a Bypass-damper that allows air from the Supply-Air ductwork back into the Return-Air ductwork if too much air pressure in the ductwork exists.  The Bypass-Damper opens only if needed, and remains open only as long as excess pressure exists within the ductwork.

Click Here To Read About Energy Star Rated HVAC: Energy Star Rated HVAC

 

Thermostat Controlled, Electrically-Operated Dampers Create Zones Within A Single HVAC System

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Shown: Electrically Operated HVAC Zoning Damper

Click Here To See An Image Depicting Various Heating & Cooling Zones Inside A Home: Zoned HVAC Diagram

With Upgraded, Variable-Speed & Zoned HVAC Systems

In a two-story home, you can have both floors at the same temperature.  The dampers will reduce the amount of cooled / heated air going to either floor to ensure the entire home is the same temperature.  Additionally, you can install as many dampers as you wish, for as many Zones as you desire.

You also have the option to reduce the amount of cooling / heating going to the floor which is not being used.  At night, the first floor can receive less heating or cooling than the second floor.  During the day, the second floor can receive less heating or cooling.  This will lower heating and cooling costs without reducing comfort.

This works the same way in a single level home.  Dampers can be installed to separate daytime living space from bedrooms, or any combination you choose.  If you seldom use some rooms, they can receive little or no heating & cooling when not being used.  In a large home, this can considerably reduce the amount of time the HVAC System runs, and reduce heating & cooling bills accordingly.

Another Option If You Need To Cool & Heat Only A Few Rooms In A Large Home

Ductless HVAC 

You don’t have to replace your Central HVAC System to get Zoned HVAC in just a few rooms.  If you would like to cool / heat only a few rooms, there is a modestly-priced solution that can be installed with your existing HVAC System left in place.

Ductless HVAC Systems allow you to choose to cool / heat only selected rooms (with Ductless) or the entire home (with the existing Central HVAC System).  Ductless HVAC Systems are designed specifically to cool / heat in zones, with each zone having its own thermostat.  The System knows to speed up or slow down based on how many zones are being served.

A Ductless HVAC System Connects The Outdoor Unit To The Indoor Duct(s) With A Refrigerant Line (no ductwork is needed). 

A Ductless HVAC System can cool one, or up to several rooms, depending on its size and configuration.   These Systems include a Heat Pump for heating during winter.  Ductless Systems can be installed with your existing HVAC System remaining in place.   The most common indoor duct is the one shown below.

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Shown: Components For A Typical Ductless HVAC System

If you don’t like the large indoor duct shown above (at top of picture) there are various indoor ducts available for Ductless HVAC Systems.  The one shown below (at top of picture) recesses into the ceiling.  It intakes air in its center and delivers conditioned air in up to 4 directions.  There are many Ductless HVAC vent designs available.

 

Image Source: Amazon Affiliates

 

There Is Another Option For Cooling & Heating Only 1 Room

There are heat pumps that look like a window a/c.  They install in the window with no modifications or special wiring required.

SHOWN: Frigidaire 8,000 BTU Air Conditioner / Heat Pump Operates On Standard 115 Volt Wiring (what’s already in the room)

Click On Image To: See Product, View Details, or Purchase From Amazon.com

 

If you don’t want an A/C / Heat Pump hanging out a window, there is a stand alone option with hoses for outside air intake & exhaust.  These units are typically on wheels and can be rolled from room to room.

From the author’s personal experience, these units create more noise (because all working components are inside them, thus inside the room).   They don’t seem to perform quite as well as a window unit (possibly due to air-volume restrictions created by the hoses).    They do a good job, and provide an option for those who don’t want or can’t have, a window unit visible.

Shown: Whynter 14,000 BTU Free-Standing, Dual Hose (hose intake air & exhaust from outside the home)

Operates On Standard 115 Volt Wiring (what’s already in the room)

Click On Image To: See Product, View Details, or Purchase From Amazon.com

 

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This Article Is About Variable-Speed & Zoned HVAC.  Al’s Plumbing, Heating & A/C, in Plano, Texas provides full service plumbing maintenance, repairs and replacements for every plumbing component in your home.  Al’s sells and installs Rheem Professional Series gas & electric water heaters, and tankless water heaters.  Al’s Plumbing, Heating & A/C is near your home in Murphy, Wylie, and Rowlette, Texas.  We service all homes in southern Collin and Denton Counties with no additional travel charge.

Al’s also provides maintenance & repairs for all brands of Central A/C, Gas & Electric Furnace, and Heat Pumps.  Additionally, we sell and install new HVAC Systems from American Standard (same company as Trane), Ameristar (same company as American Standard) and Coleman HVAC (same company as York HVAC).