This Is Part Of A 4-Part Article

Click Here To Read Part 1: Heat Pumps Part 1 of 4

Click Here To Read Part 2: Heat Pumps Part 2 of 4

Click Here To Read Part 3: Heat Pumps Part 3 of 4

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/


american standard platinum gold silver series hvac


Heat Pump Characteristics — Part 4 of 4

Considerations When Buying A New HVAC System With A Heat Pump

When Cooling — Heat Pumps Operate The Same As Central A/C.

When Heating — Heat Pumps Have Unique Operational-Characteristics. 

central air conditioner outside unit

Image Source:


One Of The Biggest Complaints About Heat Pumps Is The Noise They Make During The Defrost-Cycle

  • As temps drop below freezing — the moisture in the air passing through the outdoor unit freezes on the coils.  At recurring intervals, the Heat Pump Defrost-Cycle melts the frost, then returns to heating-mode.
  • When a heat pump defrosts — the outdoor unit changes from Heating-mode into Cooling-mode.   While defrosting — the Heat Pump removes heat from the house and moves it into the outdoor unit.  This warms the outdoor unit’s coil — and melts any frost.

Image Source: YouTube Embedded Video

Shown: Heat Pump outdoor unit with accumulated frost on its coil.

Click on white arrow (in center of image) to watch the Heat Pump defrost.


How Does A Heat Pump Know When To Defrost?

  • Once the outdoor temp drops to 31 degrees — the Defrost-Sensor (in the outdoor unit) activates.  
  • The Defrost Control-Board (inside the outdoor unit) — initiates defrost-cycles when certain conditions are met (just below).
  • With Timed-Defrost — the outdoor unit keeps track of how long it has run.  When the accumulated, total run-time is met — the outdoor unit defrosts.  Whether it needs to or not.
  • With Demand-Defrost — once a specific amount of frost has built up — the Heat Pump performs a defrost-cycle.  It only defrosts when needed.


Steps In A Heat Pump Defrost-Cycle:

  • HVAC System activates the electric heat-strip inside the furnace.  This allows the HVAC System to provide heat to the home during the Heat Pump’s defrost-cycle.
  • The outdoor unit’s compressor shuts off briefly.
  • The refrigerant reversing-valve changes position.  This changes the Heat Pump from heating into cooling-mode during defrosting.  This is to warm the outdoor unit and melt any frost.
  • The outdoor unit’s compressor turns on.
  • Note: The fan (at the top of the outdoor unit) — does not run during defrosting.

The Heat Pump Is Now In A Defrost-Cycle.

  • The outdoor unit heats up quickly — melting the frost.
  • Defrosting continues until the defrost-sensor reopens.  This tells the Heat Pump there is no longer frost present.
  • The defrost-sensor resets — to monitor if frost may be occurring.
  • The outdoor unit reverses back into heating mode.
  • The Heat Pump resumes heating.

Before You Buy — Ask If The Heat Pump Has Demand-Defrosting  OR Timed-Defrosting.

Then you’ll know — and can make an informed purchase decision.

Some Heat Pump brands or models have “Demand-Defrosting”.  They only defrost when needed.

Example: American Standard & Trane HVAC Heat Pumps (made by the same company) — include Demand-Defrosting.  Al’s sells American Standard HVAC Systems.  There are also other brands with Demand-Defrosting included.


Most Heat Pump brands have Timed-Defrosting.   Once  the outdoor unit has run for a certain length of time, the Heat Pump defrosts — whether it needs to or not.


Some Less Expensive Brands Of Heat Pump Have Select Models With Demand-Defrost.

Example: Some Coleman HVAC Heat Pump models have Demand-Defrost.   Demand-Defrost models have a higher HSPF Efficiency Rating (Heating Season Performance Factor) — partly due to having Demand-Defrost not causing needless defrost-cycles.  Al’s sells Coleman HVAC Systems.

Example:  Goodman & Amana HVAC Heat Pumps (made by the same company) — have Timed-Defrosting.  There are many other brands with Timed-Defrosting.

Depending on how the Goodman / Amana Heat Pump outdoor unit is set — it defrosts every 30, or 60, or 90 minutes of total outdoor-unit run time.  The outside unit keeps track of the minutes it has run since the last defrost cycle.

NOTE:  A Demand-Defrost System Can Be Added To A Timed-Defrost Heat Pump. **

Once the outdoor temp drops to 31°F — Timed-Defrost Heat Pump defrost every 30, 60, or 90 minutes (depending on how it was set when installed).  One type of Add-On Intelligent Defrost System has a refrigerant pressure-sensor that measures the difference in the refrigerant’s pressure between the indoor coil (inside the furnace and can’t be seen without removing a panel) and the outdoor unit. **

With no frost on the outdoor unit — the difference in refrigerant-pressure is minimal.   As frost accumulates — the difference in refrigerant-pressure increases.  The System described in the article ** tells the outdoor unit to defrost once enough frost has accumulated to reduce the Heat Pump’s efficiency by -25%.   There are likely other brands of this type of product available. 

** Source:

NOTE: This Is Not An Endorsement For The Product Described ONLY Because Al’s Does Not Have First-Hand Knowledge About it.


When A Heat Pump Defrosts (when not needed) — It Wastes Electricity. 

  • The Heat Pump removes heat from inside the house to heat the outdoor unit.
  • During defrosting, the HVAC System activates the supplemental-heat (inside the furnace) — so cold air doesn’t come out the ducts during defrosting.
  • This is electric heat, and it’s notably more expensive to run than the Heat Pump.
  • Once the defrost-cycle is complete, the Heat Pump must then replace the heat it removed during the defrost-cycle.
  •  The cost to convert a Heat Pump from Time-Defrost to Demand-Defrost will be repaid in electricity savings over time.


Additional Heat Pump Characteristics

  • Heat Pump Characteristics: Heat Pumps make noises (when heating) that a central a/c doesn’t make.  These noises are mostly during the defrost-cycle.  
  • Heat Pump Characteristics: Due to lower heat output-temperatures — A Heat Pump HVAC System runs longer than a furnace.  Running time continues to increase as outdoor temperatures drop.
  • Heat Pump Characteristics: Output-Air Temperature (at the air vents) is notably lower than a gas or electric furnace.  A furnace produces heat at 130-150 degrees.  On a 35 degree day — a Heat Pump produces heat at 90-95 degrees (which is enough to heat your home).  As the outside temp drops lower, the air coming from the vents will drop more.
  • In above-freezing outdoor temperatures, Heat Pump output-temperatures are enough to heat the house.  If at any time outdoor temps drop enough that the Heat Pump can’t keep up — the electric, supplemental-heat turns on.   When the heat-strip (inside the furnace) is running — output-temperature at the vents will rise notably.
  • Heat Pump Characteristics: Unlike a furnace — turning the thermostat 2 or more degrees higher will heat the house faster with a Heat Pump HVAC System.  Heat Pumps have Two-Stage Heating.  Stage 1 is the Heat Pump only.  Stage 2 is the Heat Pump PLUS electric supplemental-heat.   With a furnace — turning the thermostat higher doesn’t heat the house faster, it only heats longer.
  • Once the home’s temp is within 1 degree of the thermostat setting — Stage 2 / Supplemental, electric heat turns off and the output-temperature (at the vents) drops into the 90-95 degree range (because only the Heat Pump is running).  Using electric back-up heat costs up to three times more than running the heat pump (depending on outdoor temp) — so a Heat Pump HVAC System runs supplemental-heat only as needed
  • Heat Pump Characteristics: A 2-Stage Thermostat is required with a Heat Pump.  This type of thermostat runs the Heat Pump only (Stage-1 Heating) — this is most of the time.  When the Heat Pump can’t keep up — the thermostat turns on the supplemental, electric heat (Stage 2) and runs both heat pump & electric heat.   Once the indoor temperature is within 1 degree of the thermostat setting  — the thermostat returns to Stage-1 Heating (Heat Pump only).
  • Heat Pump Characteristics: A Conventional Set-Back Thermostat can’t minimize heating costs with a Heat-Pump.  A Conventional Set-Back Thermostat simply increases the temperature at the designated time — causing the electric back-up heat to operate.  Then it returns to single-stage (heat pump only) heating.

NOTE: Without a 2-Stage Thermostat, with a Heat Pump — it’s less expensive the keep the thermostat at the same temperature all the time.


  • To fully minimize heating costs — a Smart Thermostat is required.   To understand why a Smart Thermostat fully minimizes Heat Pump heating costs, see below.

Most Smart Thermostats minimize Heat Pump heating costs — by minimizing the amount of time the electric, supplemental-heat runs.

This also works with the Smart Thermostat’s automatic temperature set-back feature. 

nest thermostat in heating mode

Image Source: ShutterStock

SHOWN: The Nest Smart Thermostat Displays An Orange Background When Set To Heating

The NEST Thermostat’s “Heat Pump Balance” Feature — allows you to choose how fast you want your home to rewarm (after the time the heat was lowered).

You Can Choose:

  • Heat Pump only.  This rewarms the home the slowest — and costs the least.  Nest calls this: ” Max Savings“‘
  • Heat Pump + electric supplemental-heat (thermostat regulates).  This balances heating costs with comfort.  Nest calls this: “Balanced”‘
  • Supplemental electric heat only.  This rewarms the home the fastest — and costs the most.  Nest calls this: “Max Comfort”.

Click Here To See Nest Thermostat (while in Heat Pump Balance setting) — asking which heating mode you want: Nest Thermostat With Heat Pump Balance Feature Settings

Click Here To See A Nest Thermostat Advising Stage-2 Heat Is Running:  Nest Thermostat Advising Stage-2 Heat Is Running


When Using Nest’s Heat Set-Back Feature:

  • Goes online to get the outdoor temperature.
  • Nest estimates how long it will take your reheat your home.  This helps the Nest decide how much time is needed to operate each stage of your heating system (heat pump only OR heat pump + supplement heat.)
  • If the 1st stage of heating (heat pump only) won’t reach your desired temperature soon enough — the Nest Thermostat activates supplemental heat to heat the house faster.
  • The Nest Thermostat displays which stage of heating is active by displaying “AUX. HEAT” (Auxilliary Heat) — when both the heat pump + back-up heat are running.

two central air conditioner outdoor units

Image Source:

Additional Considerations When When Considering Buying A New HVAC System

(Or A Conventional Central A/C + Furnace)

  • Air Conditioning has become dramatically more energy-efficient over the years.    Today’s ultra-high efficient air conditioners (up to SEER-24) are up to 4 times more efficient that one built before 1980 (SEER-6).  And this assumes the pre-1980 a/c is working at its like-new capacity (which is unlikely).  Even a properly maintained A/C likely loses efficiency as it ages, due to normal wear & tear.

If you have a Central A/C older than 1998 (SEER -8) —  in many cases it’s less expensive to replace it with a more energy-efficient system — taking into consideration:

  • purchase cost
  • operating costs
  • repairs that will likely be needed on older units
  • If your current A/C uses R-22 refrigerant (freon) — tt’s very expensive to recharge it.  Freon refrigerant was discontinued in the U.S. because it harms the ozone-layer above the earth.  No new HVAC systems use freon.

The Chart Below Shows SEER Efficiency Ratings of Air Conditioners based on when they were made

  • This information is on the silver tag on the outdoor unit.
  • A new air conditioner or heat pump installed today in DFW must have SEER of 14 or higher.  This means it may be twice as efficient as a system installed in 1980-85.
  • Many outdoor units show the SEER, and nearly all will have the date of manufacture.   If your current a/c was installed as late as 2005, a new system can be as much as 40% more efficient (SEER-10 versus SEER-14).
  • Before 1980    SEER 6 or lower
  • 1980-1985       SEER 7 or lower
  • 1986-1991        SEER 8 or lower
  • 1992-2005       SEER 10-12
  • 2006-2016      SEER 13 or higher
  • 2016-                SEER 14 is minimum that can be installed in TX


Click Here To See The Silver Tag On A Central A/C Outdoor Unit With Date ManufacturedOutdoor Unit Silver Tag With Date It Was Manufactured.

Click Here To See The Silver Tag On A Central A/C Outdoor Unit With Type Of Refrigerant Used: Central A/C Outdoor Unit Tag

(It shows the refrigerant is R-22 — typically called Freon).

Click Here To See The American Standard Heat Pumps Brochure: American Standard Heat Pumps Brochure

American Standard’s / Trane’s Highest (cooling) SEER Today Is Rated Up To SEER-22. (Min. SEER is 14)

American Standard’s / Trane’s Highest (heating) HSPF=10. (Min. HSPF is 8.7)


  • According to the U. S. Department of Energy, a new Energy Star rated Heat Pump will save up to 20% on heating & cooling bills — if your existing Heat Pump is more than 15 years old.
  • A new, standard-efficiency Heat Pump installed in DFW today has a Cooling SEER  of 14 (Seasonal Energy Efficiency Rating).
  • A new, standard-efficiency Heat Pump installed in DFW today has HSPF of 8.7 (Heating Season Performance Factor).
  • Ultra High-Efficiency Heat Pumps have SEER as high as 24 and HSPF = 13.
  • Finding HSPF rating on old Heat Pumps is difficult — but you can use SEER as a guide.  If the SEER doubles, the cost to operate the system should roughly be cut in half.  This can be a guide as to what you may expect with heating cost savings with a new, higher-efficiency Heat Pump.
  • Operating costs include: energy usage, maintenance, repairs and refrigerant recharges (if leaking).  If your existing Heat Pump is needing nothing more than routine maintenance — energy savings alone may not justify the cost of replacing it.  If it’s requiring recharges of R-22 Refrigerant (freon) recharges and / or repairs — the cost to replace it may be well justified.


Additional Information About Who You Buy An HVAC System From

two central air conditioner outdoor units

Image Source:

Larger Homes Benefit From Two Or More HVAC Systems

The system’s installation is at least as important as the brand.   A poorly installed, High-Efficiency HVAC System may perform more poorly than a correctly installed, Standard-Efficiency system.

  • Value-brands (except Goodman — they make their own & Amana) — are typically made by the same companies that make premium brands.  Read the details with the link below. **
  • Value-brands, such as Ameristar (made by American Standard) don’t have the same components as American Standard / Trane (Copeland brand compressor versus ClimaTuff brand compressor).
  • This doesn’t mean Value-brands are bad — simply they likely don’t live up to the performance of Premium Brands.
  • Value-brands have fewer features & options — and most do not offer an ultra-energy-efficient models.


Ameican Standard & Trane are premium-priced brands.  Not everyone needs, wants, or can afford a premium brand.

  • American Standard & Trane are the only brands with their own, proprietary, ClimaTuff compressor.
  • American Standard’s Platinum Series top model A/C has a SEER-22.
  • American Standard Gold Series top model A/C has a SEER-17
  • American Standard Silver Series top model A/C has a SEER-16
  • Ameristar’s top model A/C has a SEER-14  (Ameristar has a Copeland brand compressor).  SEER-14 or higher is required in Texas.

This may help one choose which system (premium or value) is best for you:

  • For those with a large home and/or someone who is home all day, a premium-priced, higher SEER System may be the best choice.
  • For those with a small home and/or no one is home during weekdays, a value-priced, lower SEER may be the best choice.


** Click Here To See Who Makes Specific HVAC Brands:  6 Companies Make Nearly All HVAC Brands


Where & How To Best Spend Your Money To Lower Heating & Cooling Costs

photo of blown insulation in an attic

Image Source: Shutterstock

Today’s Texas Building Code For Attic Insulation is R-38

You Can Decrease Cooling & Heating Bills Two Ways:

  • With a lower rated SEER / HSPC Heat Pumpwith a well-insulated home with air-leaks sealed.
  • With a higher rated SEER / HSPC Heat Pump with a poorly insulated home with unsealed air leaks. 


How Much Insulation & Air Leakage In A 1970 Built DFW Home?

Brady Bunch House

Photo Source: Dreamstime

Do You Recognize This Famous 1970’s House?  (Hint: “The Brady Bunch”).

  • In 1970 Texas Attic Insulation Requirement = R-19. 
  • Today, Texas Attic Insulation Requirement = R-38 (twice as much).
  • Through 2014 — there was No Standard For Air-Leakage in homes. *2
  • In 2015 the  International Energy Conservation Code (IECC) was established. *2
  • Today’s newly built Texas homes cannot allow more than 5 Air Changes per Hour (ACH) — and not less than 3 ACH (indoor air exchanged with outdoor air). *3
  • At least 3 ACH is required to maintain Indoor-Air Quality.
  • When the ACH is less than 3 — Mechanical-Ventilation is added. *3

A study was performed by Dow Chemical to discuss the effects of air leaks in existing homes.  On Page 20 — there is a chart with the following results:

Whole-House Air Changes Per Hour (ACH): 

  • Newly Built DFW Homes: around 1.2 ACH *4.  The home requires mechanical-ventilation to maintain indoor-air quality — see details below in: “Continuous-Operation Bath Fan”.
  • 1970 Built DFW Home: 10.6 ACH — or higher! *4
  • Due to different construction methods & technologies when the 1970’s home was built — sealing air leaks won’t make it as tight as a newly-built home.
  • BUT — an older DFW home can achieve up to a 20% reduction in heating & cooling costs when air leaks are sealed. *5

The International Association of Certified Home Inspectors created a manual to explain the value of these air sealing measures.  Studies showed the measures (described in the guide) can typically reduce whole-house energy usage by up to 20%.

Click Here To Read The U.S. Dept. Of Energy Guide To Air Leakage In A Home: *5


How & Where To Spend Your Money To Lower Heating & Cooling Costs

  • If you have a home built before 1990, you will likely get a better return on your money by purchasing a lower SEER / HSPF Heat Pump PLUS Insulation PLUS Sealing Air Leaks. 
  • The older your home, the more return you will see on energy-saving measures.
  • If you have a home built 1990–2015, you may get a better return on your money with a lower SEER / HSPF Heat Pump PLUS Sealing Air Leaks.
  • If you have a newer home 2015 or later — your home is built to today’s Energy-Conservation Standards.  Your HVAC system is rated at today’s standards too.
  • They are  SEER=14 & HPSF=8.2 (if you have a Heat Pump) or higher in Texas.



*4 SOURCE:     (Page 20).


Continuous-Operating Bath Fan (To Provide Mechanical-Ventilation For The Home)

If you own a home built around 2000 or later — you may wonder why there’s a bath fan (typically in the owner’s-suite bath) that you can’t turn off.    Today’s homes are built very tight.   The benefit is lower cooling and heating costs.

These tighter homes also create a side-effect — indoor-air quality can suffer.  This is because the home is so well sealed that it can’t get enough ventilation without a mechanical-venting system.  Humidity and toxins built up inside a tightly sealed home can lead to breathing and health issues for the occupants.

DFW is in Climate-Zone 3.  A home in DFW must have at least 3 Air Changes per Hour / ACH (exchanges of indoor air with outdoor air) — to ensure acceptable indoor-air quality.  Newly built homes have so little air leakage that they don’t meet the 3 ACH requirement without mechanical-ventilation.

This is why many newer DFW homes have a continuously-operating exhaust fan.  This fan provides a way to exhaust stale air & humidity hat builds up inside a home. The fan’s airflow rate is set to achieve only the number of air-exchanges per hour required for that specific home.

Don’t Disable The Continous-Operating Fan.  Without it — toxins & moisture will build up inside your home.  This fan only removes the amount of air required to meet the 3 ACH requirement in DFW.

These are typical pollutants found in a home’s indoor-air:

  • water vapor / humidity
  • radon
  • mold spores
  • carbon monoxide
  • formaldehyde
  • Volatile Organic Compounds (VOC’s).  The most easily identified VOC is a “new” smell.  Like the smell from new paint, carpet, wood floors and furniture.

The number of Air Changes per Hour (ACH) temporarily increases when any of the following devices are running:

  • clothes dryer
  • vented kitchen range hood
  • bath vents
  • Fireplace is being used.  This continues to happen until the fireplace damper is closed (once the fire has gone out).

The Environmental Protection Agency (EPA) estimated that (nationally) homeowners could save an average of 14% on heating & cooling costs

By Sealing Air Leaks & Adding Attic Insulation in homes built prior to 1990.  *6 



Heating & Cooling Costs Are Also Notably Affected By Your Lifestyle Habits

dirty air filter on left. New air filter on right.

Image Source: CanStockPhoto

Many people don’t give much thought to how our lifestyle increases (or decreases) heating & cooling costs.

  • According to the U.S. Dept. Of Energy (DOE) — ensuring the furnace filter is changed as needed will provide energy savings of 5 — 15% year-round.  **
  • A clean furnace filter also makes your HVAC System last longer.  With a dirty furnace filter — the HVAC System must run longer & harder than with a clean filter.   This shortens its life.
  • The US Department of Energy (DOE) says: “A clogged central A/C outdoor unit increases energy usage by up to 30%”.  This causes the HVAC System to run up to 30% longer & harder — and shortens its life.


Click Here To See A Clogged A/C Outdoor Unit: Clogged Central A/C Outdoor Unit


Maintaining A Clean Furnace Filter & Outdoor A/C Unit Can Cut Cooling Costs By As Much As One-Half !


** Source:


For in-depth details about the topics just above, and much more, click on the link below for an article from our Blog:

55 Ways To Lower Cooling Costs WITHOUT Buying new A/C


For in-depth details on air conditioner performance, click on the link below: 

Is Your A/C Performing At Its Best? — 5-Part Series



Heat Pumps offer a lower heating-cost option for those who own an all-electric home with an electric furnace.   In DFW, operating a Heat Pump reduces heating costs, as much as 1/2 (as compared to heating with an electric furnace.  If your all-electric home currently has central a/c — nothing more is needed to install a Heat Pump.

NOTE: A gas furnace is less expensive to operate than a heat pump.  If your home has natural gas service inside the home — a gas furnace is your best heating option.  If your home is all-electric, and natural gas lines run near your home, —you could run a gas line to the furnace location and convert to gas heat with a new gas furnace.  But converting to gas heat it likely cost-prohibitive — as compared to a Heat Pump HVAC System.




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, TX; Allen, TX; and Frisco, TX .  We service all homes in southern Collin County, TX, and Denton County, TX with no additional 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.