Making a Store More Comfortable and Energy Efficient

Our friends work at this local tile store, and were complaining that already in the end of May the air conditioning could not keep up. Customers have been complaining about how uncomfortable it is. So I was asked to inspect the building and make some recommendations. This is the report:

What is good about this building:
By accident this building is passive solar. All the glass faces 20 degrees within south. The awning keeps the sun off the glass during the summer. But when the sun is much lower in the winter, plenty of sunshine comes in the glass, greatly reducing winter heating costs. A steep bank behind the store shields the cold winter winds from the building.


What can be done to make this building much more comfortable and energy efficient:
In my opinion, the greatest improvement can be made by increasing the ceiling insulation. The existing insulation is typical metal building roof batts, squeezed between the metal structures of the roof. Where the insulation is thickest, it might be R11, but every 36" this insulation is pinched between the metal framing, reducing its value to almost nothing. The minimum insulation required by code is R-38 in our area, and I recommend that more insulation be added to meet this code. This may be done by removing the wood framing, installing light gauge metal firring channels across the bottom of the beams at 24" on center, rewiring the ceiling lighting and fans at this level, and closing up the ceiling with 5/8" sheetrock. Not only will this improve the energy efficiency and comfort, but it will open up the ceiling of this showroom, making it look more professional and inviting. The existing wood framework is sagging, difficult to clean, and doesn't look very good. After this is done, new exposed ductwork can be hung from the ceiling.

The next item for improvement is the ductwork. I don't feel comfortable criticizing someone else's work, but the ductwork in this building was very poorly designed and installed. One plus is the majority of the ductwork is inside the air conditioned area. Ductwork in the attic gets so hot, the air conditioner has to work much harder to cool the building. But the other half of the ductwork is in the hot attic. So is the air conditioner. The poor unit is running all day long, non stop, trying to overcome the attic heat in order to cool the building. How much energy would you have working up there all day? But there is another problem that's even more serious with the ductwork. Look at the photos below at how badly pinched the ductwork is. What happens to the water coming out of the garden hose when it is pinched like that? The same thing happens to the cold air. It doesn't blow into the offices below. This ductwork probabley leaks too. I did not see any mastic painted on the ductwork. Tape alone is not good enough. So I recommend the ductwork be replaced, and the air conditioner be placed inside an air conditioned area, insulated from the hot attic air. The air conditioner will run much less and last much longer. I also recommend that the entire duct system be brought inside the air conditioned area. These changes should reduce the air conditioning costs by more than 10%.

While doing this, I recommend that the bathrooms be separated from the air conditioning system. When I inspected the building, the air conditioning had been running continuously for hours, and the air coming out of the registers in the bathroom was warm. The long skinny flex duct in the photo below does not allow the air to flow quickly enough, and the hot air surrounding the duct warms up the air inside. Another problem is the poor insulation job done on the bathrooms. Fiberglass insulation is worthless if there are any gaps for air to leak through. The one place I checked, I found a 2" wide gap. Because these bathrooms are so far from the rest of the air conditioned area, I don't believe it would be worthwhile to use one system for both areas. If the bathrooms were not air conditioned at all, they would be no less comfortable than they are right now. If they decide the bathrooms must be air conditioned, I recommend a small, separate system.

The next area to consider is the air conditioner. I spoke with the factory, and they told me this system has a SEER rating of about 10. This is far below the minimum required by code. The unit is so inefficient that if they borrowed money to upgrade it, they would probabley save more money in electricity than they would spend on the new payment. For example, if they replaced this sytem with a 15 SEER unit, they would reduce their air conditioning costs by 1/3. I recommend that they talk to the electricity company about any programs they have available for upgrading the air conditioner. If they qualify for one of their programs, the electric company will require that the work be inspected by them before they approve it. For a new enery efficient air conditioner to perform well it must be installed correctly.

The next area to comsider is the lighting. Some of the bulbs have been replaced with fluorescent lamps. But I still counted 42 incandescent bulbs that are running all day, and 8 more in the bathroom. If these run all day long, they probably burn about 90 kwhours per month. Replacing them could reduce their lighting costs by $12 per month. But that is not all. The reason incandescent bulbs use more electricity while making less light is that much more of there energy is wasted making heat. That heat adds to the problem in this building, making it more uncomfortable, and making the air conditioner run more.

The last area to consider is adding some landscaping. If they would plant some deciduous trees (those that lose their leaves in the fall) on the west and east side of the building, they would keep a lot of hot summer sun off the building. These trees don't have to be right next to the building, just close enough to add some shade in the future. This would also frame in the front view of the building, making it more attractive to their clients.


New Homes I have Designed
Remodeling Projects I have Designed.
My Procedures for Designing and Planning


Richard C. MacCrea
Home Planner

For a written proposal, including the cost of plans, make a free, no obligation appointment.

Email Richard
P.O. Box 446, Murphy, North Carolina 28906-0446
(828) 837-5787


Other Pages on this Web Site
The Mountain Home Show, Home Page and Site Map (How to find what you're looking for)
Detailed information about the home show (For guests and exhibitors)
Articles (About designing, building and remodeling a mountain home)
The Mountain Model Home (An experimental home that is extremely energy efficient)
The Mountain Model Cabin (A very small mountain cabin designed to sleep four comfortably)
Construction Diary (The joys and frustrations of building these two model homes)
Home Designing and Planning (How to get great plans for building or remodeling your home)

How to Contact The Mountain Home Show
Email Us (Questions about The Mountain Home Show or Your Mountain Home Project)
The Mountain Home Show, P.O. Box 446, Murphy, North Carolina 28906-0446


Appreciation......
The Mountain Home Show owes its success to the businesses that participate in the show. They arrange such wonderful exhibits. It is obvious that they take great pride in their work and our show.


This web site contains information obtained from various sources. The Mountain Home Show is not liable for the accuracy of this information. Please contact the source of this information with your questions.