4 Mini-Splits and Heat Pump Efficiency, Will It Work?

Yes, I drive tractors too. Along with the home energy audit work, I’m a farmer at heart. I received a call from a gentlemen that needs some help backfilling and leveling out the dirt around the foundation of his homes new addition.

Now that the ground is dry enough, I load up my 24 horsepower Kabota tractor with bucket, attach the tiller and head over to his place. I find an old original house that was constructed shortly after the wagon trains arrived. Attached to the side is the new addition that really stands out and looks great.

Out front, facing the road, is the new two car garage. It is unmistakable a new garage. The new siding, paint and the gargoyles over the garage entrance update the structure. What you don’t see from the street is the hobby room, three bedrooms and two baths behind the garage. I was lucky enough to get a tour of the new digs after I got through with the outside dirt moving.

I got a new surprise when I turned the corner on the back side of the addition. I have never seen this before and it took me a few minutes to realize what I was looking at. Coming out of the concrete foundation, just above dirt line, were four sets of insulated copper lines and four sets of 1/2 inch PVC pipe. Could this be future heat pump efficiency?

I could be wrong, but it looks like this guy is going to install four heat pumps behind his house!

Why Four Heat Pumps?

About this time, the homeowner and I got into a little discussion concerning how he was planning on heating and cooling this addition. Come to find out, he has it all planned out and, it seems to me, he has a great, energy efficient plan.

Here are the major points to his energy saving plan and heat pump efficiency.

1. During construction, while the interior and exterior walls were open, he had four mini-split heat pump units installed and the refrigerant lines put in place. Since the walls and underfloor areas were accessible, he could mount the units on interior walls. One in each bedroom and one in the hobby room.

2. Each heat pump unit will have its own outside coil, compressor, indoor coil, and air handler. Each room also has it’s own wireless thermostat control.

3. The three bedrooms and the hobby room are heated and cooled separate from the other rooms. One room could be 60 degrees and another room could be 70 degrees.

4. The four heat pump units were purchased by the homeowner on Amazon. No doubt there was free shipping. The heat pumps were being installed by a local heating contractor.

5. The two bathrooms are heated by electric radiant floor heat under nice tile flooring. As an addition to control moisture and increase energy efficiency, the ceiling exhaust fans in the bathrooms are 130 CFM, variable speed, .6 Sones, motion activated with timers. These are great exhaust fans, we will have to talk more about them in another article.

More About the Heat Pumps:

The heat pumps have Evergreen Products written on the front, they are made by Soleus. They are rated at 9,000 btu and are connected to 115 volts with a 15 amp fuse. Cooling Seer is 13.5 and the heating Hspf is 9.0. Operating, they draw 7.3 amps.

I asked the homeowner what he thought the impact on his electric bill was going to be considering he had four heat pumps. He said he expected it not to rise too much more than it was already. Come to find out, his electric bill for the month of June was a few cents over $15.

Now, that’s a little hard to believe, unless you take into consideration the 12 or so solar panels neatly mounted on the roof. Now I am really beginning to like this guy. Heat pump efficiency and solar electric power.

Let’s take a closer look at energy efficiency and how this home is performing.

1. He has Solar Electric panels on the roof generating all the electricity he needs in the sunny summer months.

2. He has constructed an addition where he installed an inch of spray foam insulation on the inside of the exterior walls before he install dense pack cellulose.

3. Individual rooms are being heated and cooled with just about the most efficient heating source known to man, the minisplit ductless heat pump.

4. Radiant floor heat and performance ceiling fans make using and maintaining the bathrooms a snap. Even the kids can get the bathrooms to function right.

5. The heat pumps were purchased online during a closeout, super deal sale. I don’t know what he paid for them, but you can buy the same units online today for $460.

Just look at the comfort and energy efficiency involved with this addition.

  • Heat and cool with ductless heat pump efficiency. When you heat and cool this way, no heating ducts, you never have to worry about the heating ducts leaking.
  • Individual room heating and cooling systems. You only spent dollars on heating or cooling the rooms you need.
  • Spray foam insulation air seals the exterior walls before the cellulose goes in.
  • Solar Electric array provides clean renewable energy which then offsets the power needed to operate the heat pumps.
  • The bathroom ceiling fans can be set to run at a low CFM ( cubic feet per minute ) rate that freshens the house and provides needed air changes if the house is too air tight because of the heat pumps, no heating ducts, air sealing, and spray foam insulation.
  • The ceiling fans ramp up to 130 CFM the second someone enters the bathroom. The ramped up fan maintains that CFM rating until the room is without motion for a set number of minutes.

The sun was going down and the temperature cooling off a little by the time I completed the backfill work. I told the homeowner that I was planning to drop by in a couple months and see how the addition is looking and how it is performing.

I like it when I use the word “performance”. Seems to me, we really need to start teaching our homes to perform instead of us, the inhabitants, always doing the performing. You know, like the performance we’re required to do when we put on a sweater or when we wash the mold off the bathroom wall, or how well we perform when we are writing our power providers name on a payment check. Teach your home to perform with heat pump efficiency.

Thank you for stopping by Detect Energy, hope you will stop by again real soon, but I won't leave the light on for you...

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Tags: efficiency, energy, environment, heat, heating, pump, recycling, refrigerant


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Comment by Craig Senglin on July 26, 2012 at 12:46pm

If the house is really tight, those bath fans won't draw anywhere near 130CFM...and no mechanical fresh air ventilation system either?  Where will the "dew point" fall in that wall assembly?  Smells like an IAQ nightmare waiting to happen!  Homeowners rarely have the building science expertise to think of every design element necessary in a DURABLE tight home.  Hire a professional...test the bath fan flows and ACH of the building...follow ASHRAE 62.2.

Hope its not too late...

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