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Al’s Plumbing, Heating & A/C in Plano, Texas 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).

Al’s also 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 is near your home in Plano, Allen, and Frisco.  We service all homes in southern Collin and Denton Counties with no travel charges.

Call Al’s today to discuss any concerns or problems you have with your HVAC System or Plumbing.  We will arrange an appointment at your convenience and offer 24/7 Emergency Service.

 

photo of colorful fall leaves

Image Source: ShutterStock

As summer’s heat fades and fall’s cooler weather arrives, many home owners start to consider if it’s time to replace their furnace.   As detailed below, your existing furnace’s efficiency is mostly determined by its age.  In 1987, all gas furnaces were required to have a minimum efficiency of 78%.    In 2007, the minimum efficiency was raised to 80%.  In 2013, 90% is now required for northern states and 80% is still in effect for southern states.

  • A 78%-80% gas efficient furnace exhausts 20-22% of the heat it generates out of the home with the combustion gases.
  • Also, these furnaces draw combustion-air from their immediate surroundings.

If a gas furnace is in the attic, drawing surrounding air into the furnace does not matter.  If the furnace is in the living space, it draws heated air from inside the house to use for combustion of the gasses that are then vented outside.  The heated air the furnace removes is replaced by outdoor air brought inside through air leaks in the home.

You you replace a standard 80% efficiency furnace (inside the living space) with a High-E furnace (90%+) — it will draw combustion air from outside.  This eliminates using heated indoor air for gas combustion.

think green logo

Image Source: ShutterStock

 The Higher The Efficiency Of A Gas Furnace — The Less Air Pollution It Creates. 

Carbon Dioxide (CoO2) Is A By-Product Of Burning Natural of LP Gas. 

Carbon Dioxide (CO2) Is a Greenhouse Gas That Contributes To Global Warming. **

Higher Efficiency Gas Furnaces Also Conserve Natural Gas, A Natural Resource.  **

** SOURCE: http://www.belred.com/blog/the-benefits-of-a-high-efficiency-furnace/

 

One Way To Know If A Furnace Is Less Than 78% Efficient

Is By Listening To The Sounds It Makes When It Begins A Heating Cycle *   

Furnaces made in 1978 or before are less than 78% efficient.    All furnaces with 80% or lower efficiency have open holes in the front (removable) panel.  Look through the holes and you can see the burners’ flames.  These vent holes are where the furnace draws air for combustion of the gas.  The way to determine if a furnace is less than 78% efficiency is by listening to the sounds it makes during a heating cycle.

When an older gas furnace (less than 78%) begins a heating cycle:

  • You will hear the burners lighting.
  • The blower / fan motor starts in a short time.

When a gas furnace with 78% or higher efficiency begins a heating cycle”

  • *A small motor will start running before the burners ignite.  This motor moves the exhaust gasses out of the furnace and up the flue.
  • You will hear the burners lighting.
  • The blower / fan motor starts in a short time.

Furnace Efficiency Ratings Over The Years

Furnaces are categorized according to their AFUE (Anual Fuel Utilization Efficiency) rating.

Prior to 1875, most American homes were heated with wood burning fireplaces or wood burning stoves.

A. 50% Efficient — “Octopus” Furnace.  Half Of The Heat Goes Up The Flue.

Click Here To See And Read Details About An Octopus Furnace: Octopus Furnace

Click Here To See A One Minute Video Showing An Octopus Furnace In Operation: Octopus Furnace In Operation (scroll down)

  • These were the first central heating furnaces.  They were installed in homes during the late 1800’s and early 1900’s.
  • Originally most octopus furnaces burned coal.  Over the years, many were converted to heating oil or gas.
  • They do not have a blower fan to move the air.
  • They are also called “gravity feed” (definition below).   This is because they depend on the heated air to rise from the furnace into the home.  Cold air would sink into return-air registers then to the furnace (warm air weighs less than cold air).
  • Because of the gravity-feed operation the ductwork was very large as compared to forced-air furnaces.

Click Here To See The Ductwork Pipes Size With An Octopus Or Gravity-Feed Furnace (same thing): Octopus Furnace Ductwork Size

  • If a home had an octopus furnace, and still has the original ductwork, the return-air (cold) registers are along the outside walls because those walls are cooler.
  • With forced air furnaces, supply-air (warm) ducts are along the outside walls.
  • Because octopus furnaces had only a one valve for gas or heating oil, and no moving parts, they tend to last forever.  Octopus furnaces can still be found in some vintage homes.
  • It was common for these furnaces to be covered in asbestos, and / or have asbestos inside them (to help keep heat from escaping the furnace into the basement).

Click Here To See An Octopus Furnace Covered In (white) Asbestos: Octopus Furnace Covered (in white) Asbestos

 

Forced Air Furnace Efficiency Ratings Over The Years

B.  60% — 72%   Extremely Low To Very Low Efficiency Gas Furnace

  • Blower Fan Motor to move air through the furnace. 
  • Furnaces before 1970 are about 60% efficient. *3
  • Furnaces built between 1970 — 1977 are about 65% efficient.
  • Many of these furnaces will be painted green or gold.
  • Furnaces built between 1978 — 1987 are about 70% efficient.
  • Many of these furnaces will be painted shades of beige.
  • These forced air furnaces were installed in newly built homes during the 1960’s — 1980’s.
  • These furnaces were also installed as replacement furnaces in older homes.  In many cases they replaced coal or heating-oil furnaces.
  • Furnaces with these low efficiency ratings are still operational in many homes today.

These Components Will Likely Be Found In 60% — 72% Efficient Gas Furnaces:

  • Pilot Light
  • Natural-Draft Metal Exhaust Pipe.   The exhaust is hot enough to rise up the flue and outside.
  • These furnaces have a larger metal exhaust vent (see photo just below) than a 78% — 83% efficient furnace.

*3 Source: https://htoyh.com/content/replace_your_furnace.pdf

old gas furnace

Shown: Vent Holes In The Front Of An Older Gas Furnace

Image Source: CanStockPhoto

photo of properly working gas burners in a gas furnace

Shown: You Can See The Flames When The Burners Are Ignited

Image Source: ShutterStock

 

C.  78% — Low-Efficiency Gas Furnace

  • Beginning 1/1/1987 — 78% Became Required.
  • This applied to both replacement and newly built home installations.
  • These Components Will Be Found In 78% Efficient Gas Furnaces:  (Bold Features were not present on earlier furnaces).
  • Electric Gas Ignition For Burners
  • Draft Motor To Move Exhaust Gasses.  At this efficiency, the exhaust gasses are too cool to rise naturally up the flue.
  • Metal Exhaust Pipe.

 

D.  80%-83% — Standard-Efficiency Gas Furnace

Click Here To See A 80% Efficiency Gas Furnace: 80% Efficient Gas Furnace

NOTE: In The Photo You Can See:

  • The vent holes in the front panel of the furnace.  These holes are where the furnace draws in air for combustion of the gas.
  • The metal exhaust vent pipe is smaller than in the photo above.  This is because a fan now moves the exhaust gasses.
  • At the concrete block chimney you can see the adapter than was required to connect the new furnace’s exhaust vent to the larger opening the old furnace used.
  • Many of these furnaces will be painted shades of beige or shades or gray.
  • Beginning 1/1/2015 all new furnaces had to be at least 80% efficient throughout the entire U.S.
  • This applied to both replacement and newly built home installations.

These Components Will Be Found In 78% — 83% Efficient Gas Furnaces:

  • Electric Gas Ignition For Burners
  • Exhaust Draft Motor — This motor moves the exhaust gasses out of the home.   Once a furnace is 78% or higher, the exhaust gasses are too cool to rise up the flue on their own.
  • Metal Exhaust Pipe.

E. 90%-98.5% — High To Ultra-High Efficiency Gas Furnace

  • Beginning 5/1/2013 — 90% efficiency became required in the northern U.S.
  • Beginning 5/1/2013 — 80% efficiency continues to be required in the southern U.S.
  • This applies to both replacement and newly built home installations.
  • Many of these furnaces will be painted shades of gray.

Click Here To See A 90% or Higher Efficiency Gas Furnace: 90%+ Gas Home Furnace

  • Primary Heat Exchanger for heating the house.  Made of steel.
  • Secondary Heat Exchanger to reclaim the heat within the exhaust gasses.   Because this heat exchanger is wet while operating, it is typically made of stainless steel.
  • Sealed Combustion Chamber.  There are no vent holes on the front.  You can see the burners’ flames by looking through a small, glass covered opening on the front.
  • Electric Gas Ignition For Burners
  • Exhaust Draft Motor — This motor moves the exhaust gasses out of the home.   Once a furnace is 78% or higher, the exhaust gasses are too cool to rise up the flue on their own.
  • White PVC (plastic) Exhaust pipe.  This pipe could be installed horizontally because a motor moves the exhaust.
  • White PVC (plastic) Combustion-air intake.  Some of the first 90%+ furnaces had only the PVC exhaust pipe.   
  • In a few years, all High-E furnaces had the 2nd PVC pipe for air intake.

Source: https://www.thespruce.com/gas-furnace-types-and-afue-efficiencies-1824743

 

A High Efficiency Gas Furnace Includes A 2nd Heat Exchanger That Reclaims Heat From The Exhaust**

Standard Efficiency Gas Furnaces have 1 heat exchanger.  The sole purpose of the heat exchanger is to keep home air and combustion-air separate.  A heat exchanger is a structure with metal pipes.  The heat & exhaust gases flow inside the primary heat exchanger to heat it.   Then the furnace blower fan moves air along the outside of the primary heat exhanger and sends that heat into the home.

photo of heat exchanger in gas furnace

Shown: Primary Heat Exchanger Inside A Furnace

Image Source: DreamsTime

 

High Efficiency Gas Furnaces have 2 heat exchangers. ** 

  • The primary (larger) heat exchanger works in the same manner as a standard-efficiency furnace.
  • The secondary heat exchanger intakes the hot combustion gases as they exit the primary heat exchanger.
  • The gasses pass through the secondary (smaller) heat exhanger to extract the heat within the combustion gasses.
  • Once the heat is extracted, it is sent into the home and the cool exhaust gasses are vented outside.
  • The amount of heat remaining in the exhaust gasses will be 1.5% to 10% — depending on the efficiency of the furnace model.

Click Here To See A Diagram Of A High-E Furnace: High E Furnace Diagram

NOTE: The “Secondary Heat Exchanger” is just above the furnace’s house air blower (shown in green)

 

If your existing furnace is High-Efficiency:

  • It will have a PVC (white plastic) vent pipe to move the exhaust gasses out of the house.
  • Nearly all will have a 2nd PVC pipe to bring combustion air in from outdoors.

high efficiency gas furnace with two white pipes visible

Shown: A Gas Furnace With At Least 90% Efficiency. 

Furnace Show Has Both A Combustion Air Intake Pipe & Exhaust Vent Pipe Made Of PVC (white plastic) 

Image Source: DreamsTime

 

IN DFW — Heating Cost Comparison Of High-E & Standard-E Gas Furnace

EXAMPLE:  Natural Gas Costs Comparison — 2,000 Square Foot DFW Home With 4 Occupants

  • Using 97% GAS Furnace: at $9.71 per 1,000 cubic feet of natural gas        $505.00 Annual Fuel Cost – 97% Efficient Natural Gas Furnace. **
  • Using 80% GAS Furnace: at $9.71 per 1,000 cubic feet of natural gas       $565.00 Annual Fuel Cost – 80% Efficient Natural Gas Furnace. **
  • Using a Med. Eff. (HSPF 9.5) Heat Pump: at 11.3 cents / kWh             $1,085.00 Annual Fuel Cost – Electric Heat Pump 
  • Using an Electric Furnace: at 11.3 cents / kWh                                             $1,435.00 Annual Fuel Cost – Electric Furnace

 

IN DFWThese Lifestyle Factors Help Determine If A High-E Gas Furnace

Will Be Worth The Extra Cost

Cost of the High-E Upgrade (ask your HVAC contractor for prices for both standard-efficiency and High-E).  In DFW, the cost to upgrade to High-E furnace may not be justified.  In some cases, the money might be better spent on Energy Saving Home Improvements (that will also lower cooling costs).

These are the primary considerations when considering a High-E furnace in DFW:

  • Size Of Home.  The upgrade charge for High-E furnace will only be a little more for a larger furnace size.  The larger the home, the better value a High-E furnace can provide.
  • Number Of Occupants.  The larger the household, the better value a High-E gas furnace provides.
  • More occupants in the household means more heat loss due to:
  • more frequent entering and exiting of the home
  • more bath vent fans running
  • kitchen vent fan running more frequently and longer due to larger meals being prepared
  • more bedrooms being used and heated

In DFW — The Cost For High-E Upgrade With A Natural Gas Furnace

Might Be Better Spent On Energy-Saving Upgrades

It depends on the cost of the High-E upgrade.  Just above, we discussed how lifestyle in the home affects energy use, and thus the value of the High-E Upgrade Charge.   Particularly in homes built before 1980,  the following energy saving home improvements may provide lower energy costs year round.   Keep in mind that these improvements will reduce both heating & cooling costs.

1. Add Attic Insulation

photo of blown insulation in an attic

Image Source: ShutterStock

Texas Homes Insulation Levels That Were Common Or Became Required By Building-Code:

           Attic Insulation                           Wall Insulation

  • 1950’s: none                                     none
  • 1965-70: R-13 (4″ BATT)         Wall R-6 (2″ BATT)
  • 1970’s:    R-19 (6″ BATT)          Wall R-6  (2″ BATT)     *3
  • 1980’s:   R-30 (9″ Blown)        Wall R-13 (3.5″ BATT) *4
  • 2014:      R-38 (15″ Blown)       Wall R-15                         *5
  • *3 Source: https://snuggpro.com/blog/item/many-homes-built-prior-to-1980-were-built-without-insulation-in-the-walls
  • *4 Source: https://www.jlconline.com/how-to/insulation-code-change_o
  • *5 As required by the 2012 Edition of the International Building Code (IBC)

Does Your Attic Floor Currently Have The Insulation Depth / Thickness Required For At Least R-38?

If you have less than R-38 attic insulation, it’s likely more cost-effective to spend the additional money on adding insulation — instead of upgrading to High-E furnace.

  • 15″ of Blown Insulation is required for R-38 — or R-2.5 per inch of blown insulation.
  • If there is an existing 4″ BATT insulation, subtract 5″ of blown insulation for R-38.  A 4″ insulation batt has an R-Value of 13.
  • If there is an existing 6″ BATT insulation, subtract 8″ of blown insulation for R-38.  A 6″ insulation batt has an R-Value of 19.
  • Keep in mind these insulation levels will provide R-38 which is current Texas Insulation Building Code.
  • The cost to add additional blown insulation depth will be less than you think if done all at one time.
  • Check with your insulation contractor for pricing for R-38 and R-53 — which is an additional +6″ of blown insulation.
  • Insulating to thicker depths will not produce notable additional savings.
  • Keep in mind, cooling costs will also be lowered with added attic insulation.
  • Attic insulation will also make your home more quiet inside.

To Learn About Attic Insulation, Click Here: AlsPlumbing.com Lower Heating Costs With Attic Insulation

 

2. Ductwork Sealing

If Your Home Is More Than 10 Years Old

The HVAC Ductwork Is Likely Leaking Up to 30% Of Heated & Cooled Air

ductwork for hvac system

Image Source: ShutterStock

The U. S. Department of Energy (DOE) estimates typical homes lose up to 30% of the heated & cooled air from ductwork through holes, leaks, and loose connections. 

NOTE: If you install a new HVAC System, the contractor may want to replace existing ductwork.

  • If the existing ductwork in flexible, it needs to be replaced because it only lasts the lifetime of one furnace.
  • If the ductwork is metal, it may not need to be replaced.  If the new HVAC System has nearly the same amount of air flow when the blower-fan is running, the existing ductwork will work.  If the new System has higher air flow, the existing ductwork may be too small.  That does not necessarily mean it won’t work.  It may be able to be modified to accommodate the larger airflow.
  • If you don’t replace existing metal ductwork, have it tested for leakage and resealed if necessary (it likely needs resealed).  Your HVAC Contractor can do that.

Resealing Existing Ductwork Can Lower Heating & Cooling Costs By Up To UP TO 1/3!

Ductwork in older homes may not have been sealed when installed.  In other cases, duct tape was used.  Duct tape fails within days in a blazing hot DFW attic where temperatures can reach 160 degrees on a sunny summer day. **  Today duct work is sealed with non-hardening mastic at the seams and connections.  Mastic can withstand temperatures in DFW attics during summer without failing.

Click Here To See Ductwork Sealed At Seams and Connections With Mastic: Ductwork Sealed With Mastic

 

Max Sherman & Iain Walker of the DOE’s Lawrence Berkeley National Laboratory performed a” bake-test” in which sample ductwork joints were baked at temperatures of 140 to 187F degrees to test different ductwork sealing products.  They stated “Only one duct-tape product survived 3 months of the aging test.  11 Duct Tape products failed within days.” **

**Source: http://www2.lbl.gov/Science-Articles/Archive/duct-tape-HVAC.html

 

Click Here To See Several Photos Of Leaking Ductwork: Leaking Ductwork

 

For More Ways To Lower Heating Costs Without Replacing Your HVAC System, Check Out Our 3-Part Article:

AlsPlumbing.com 20 Uncommon Ways To Lower Heating Costs

 

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Al’s Plumbing, Heating & A/C in Plano, Texas 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).

Al’s also 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 is near your home in Wylie, Murphy, and Rowlette.  We service all homes in southern Collin and Denton Counties with no travel charges.

Call Al’s today to discuss any concerns or problems you have with your HVAC System or Plumbing.  We will arrange an appointment at your convenience and offer 24/7 Emergency Service.