Home with Dean Sharp

Home with Dean Sharp

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Heating and Air Conditioning 2021

Woman Adjusts Thermostat

Photo: Getty Images

Now that the weather is getting cooler…it’s time to schedule your HVAC work! HVAC contractor schedules are loosening up a bit from the summer insanity.

Some important tips: No, you probably DON’T need your ducts cleaned - ask an HVAC pro, not a duct cleaner.

A little history …

AC has been around for 119 years

Willis Carrier invented the modern air conditioner in 1902. The motivation for the first air conditioner wasn’t human comfort. The industrial revolution brought mass production and factories with massive machinery that ran hot and humid. Sometimes too hot and too humid for the wellbeing of the materials they were producing. Paper mills, publishing houses, yarn factories, chocolate factories, industrial bakeries, etc. all need to find a way to control heat and humidity.

Not popular in homes until the “summer blockbuster”

Thanks to Spanish flu and tuberculosis epidemics there was a massive "open-air" health movement happening at the turn of the century that believed indoor air as toxic and unhealthy. So the idea of closing the windows and recirculating indoor air was very unpopular. What brought air conditioning out of the factories and into the human comfort business were movie theaters in the 1930s. By the 1940’s going to the movies to escape the heat was so popular that studios started saving the biggest hits for Summer. Blockbusters were huge bombs being used during WWII that could level a city block. Hollywood coined blockbuster to describe a hit movie, and combined with air conditioned theaters the “summer blockbuster” was born. What's the general public got a taste of air conditioning at the movies it wasn't long before they started showing up in homes.


Photo: Getty Images

5 HVAC Homeowner Responsibilities

  1. Keep your condenser clean and clear
  • 12” min clear air space
  • Keep the coil fins clean and dry as possible
  • Bent Fin tool
  • Wash coil from the inside out
  • Use coil cleaner - 10-15 min then wash with gentle spray
  1. Don’ts
  • Don’t shut off registers or rooms
  • Don’t block the return air grill
  • Don’t let the house get too hot
  1. Change your filter every 90 days - Your AC filter is not primarily for YOU!
  • #1 cause of pre-mature system failure. Poor circulation leads to congestive heart failure.
  • Filters range in price from $3-$25 and in FPR (Filter Performance Rating) from 4-10.
  • HEPA filters (High-Efficiency Particulate Arrestance) can remove up to 99.7 percent of contaminants—pollen, mold spores, dust mites, etc.— but they also require significant pressure to force air through, making them too restrictive for use in HVAC systems that were not designed for them. Check with your A/C service company.
  • Electrostatic air filters - washable, less static resistance - $99
  • Set a monthly reminder or get a Filterscan WiFi alert unit ($140)
  1. Get a yearly checkup - especially for refrigerant levels - low refrigerant can damage the compressor
  2. Know where your secondary condensate drain is

How AC Works

Tonnage is a weird and archaic way to measure AC output. In fact, saying AC “output” is itself a misleading and inaccurate way to describe what AC does. Without getting into the weeds let’s talk for a second about what’s really going on with your air conditioning.

Cold is not a thing. Scientifically, cold is no-thing. Cold is a void. The absence of heat energy. So since cold is not a thing we can’t pump it into your house. What we can do is remove heat. Heat is a thing. It’s energy. We can add it to your home and, via the AC, we can remove it. Once we remove some heat what we’re left with is what we call cold.

AC use a magical liquid called refrigerant. Refrigerant transforms from a gas to a liquid at some very extreme temperatures which makes it very “cold’ and gives it the ability to first absorb and then release a lot of heat.

Your air conditioner pumps refrigerant in and out of your house in a closed loop. Inside the house a fan blows your warm house air over the cold refrigerant line which sucks a lot of heat out of the air. Then your system pumps the warm vapor refrigerant to a unit outside the house where it is recompressed and cooled off so it condenses back into a liquid and then sent back into the house to do it all over again. The part inside your home is the fan and the evaporator. The part outside is the compressor and the condenser.

Ductless mini-split solutions - condenser and cassette

  • New low wall units
  • multi-zone - one condenser, multiple cassettes
  • Recessed ceiling cassettes
  • Olympia Splendid’s Maestro Pro is the world’s 1st Mini-Not-Split AC/Heat Pump


When we replaced horses with cars we started measuring engines by horsepower. That made sense when a motor was 1 or 2 or 5 hp. But it hasn’t made sense for a long time.

When the first refrigerators and air conditioners showed up they replaced ice and therefore were originally measured in tons of ice. It also doesn’t make much sense anymore. Now we describe AC in terms of BTU’s.

If you’ve ever asked how much cooling output an AC unitWhat’s important to note is AC is all about “Tonnage“ describes how much heat is removed from a space in 24 hours. In modern day science to one ton of air conditioning capacity equals the ability to remove 12,000 BTU of heat per hour.

Energy Consumption

Each year, the U.S. uses the same amount of energy to power air conditioners as Africa uses to power the entire continent. Some architectural styles are directly attributed to the need for cooling, i.e.: the Southern wrap around covered porch.

Variable Speed Multi-Zone Systems

Imagine each room in your home having a hidden, silent AC with its own room thermostat. THAt is what a variable speed zoned system achieves.

  • Not all areas of your home handle temperature equally
  • Separating zones requires electronic dampers and variable speed AC
  • The huge energy savings comes from a single room AC running all day v. A whole house unit cycling on and off in an attempt to handle outlier rooms.
  • There are limits - most variable units only cycle down to 20%-30% capacity. That may be too large for just one room. So good zone design is critical.
  • Why would I want an air conditioner that runs longer and cools my home more slowly?”

Humidity - Variable speed compressors longer run times dehumidify your home more effectively, making you feel cooler and more comfortable at higher temps. Oversized units are terrible at removing humidity and waste $.

Short Cycling - Most of an AC’s electrical draw occurs when it turns on, not while it’s running. Single stage compressors short cycle. Prevent the proliferation of dust mites

Cleaner air - More air is cycled through the filter resulting in lower volume of contaminants.

Quiet - No air gusting into rooms. More subdued, consistent air flow. Outside - Quieter compressor

Smart Thermostats

  • Learning
  • Programable
  • Remote app control

Buy the highest SEER rating you can afford

Seasonal Energy Efficiency Ratio is a cooling to energy consumption ratio.

  • In 1992 min SEER was 10
  • 2006 min SEER was 13
  • 2015 min SEER is 14
  • SEER 15 within 5 years (2023)

Even if your air conditioner is only 10 years old, you’ll save 20% to 40% of your cooling energy costs by replacing it with a newer, more efficient model.

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