A town home in Houston presents an air conditioning problem, which comes under energy efficiency, but standard answers for a home may not suffice.
I have been conducting home inspections in the Rice Military area of Houston for years now. Mainly these inspections have been for town homes. So when a question was posed to me the other night about a town home in this neighborhood, I began to think back to various articles that I and others have written on the topic of energy efficiency, I realized that all of the standard material deals with a home on its own land. In a sense, this can fit the bill for a town home, but being familiar with these particular buildings I knew that some standards do not apply.
For example, shading a town home with a tree and other plantings can be nice, but many of these lots have no garden space. Most town homes in Rice Military fit a pattern: there is a lot with a driveway running through the middle with a yard area for the complex near the street; backyards are a patio if they exist; most of these town homes have three stories. The idea of shading the building, as we would suggest with a home, is not feasible. The specific problem in this town home is the heat is rising to the third floor. The air conditioning is set to 72F, and it is constantly running, but it does not seem to help. What can be done?
Let us begin in the attic. From the detail given, it sounds as if there is a standard amount of insulation of 14″. This is covering the joists in the attic. There is a mechanical vent, but we are not sure if it is working.There is no radiant barrier. This gentleman is not adversed to having a white roof, but they may not fit into the rules of the complex. Aright, 14″ is good (it is the minimum), but adding around 10″ would help. Each insulation is different, but I am guessing that with 14″ he has about an R36 where an R48 is considered the better option for this area (many of these builders only put in enough insulation for a R30). In fact, many builders do no fully insulate the attic, so you may find spots that have a need for insulation. After doing the insulation, I would add the foil bubble type of radiant barrier. The painted on radiant barrier is not good for Houston (moisture issues in our humid climate). I would check that the mechanical vent is working, but I would replace it with some solar powered vents. Solar vents come on when the sun is hitting the roof, when you need the hot air vented out. Moreover, I would have more than one. Typically the minimum ventilation is met, and this can be fine, but my impression is that we need a bit more in Houston.
While up in the attic, I would check my ducts for the air conditioning system. If you feel cold air, you have a problem. Adding more duct insulation cannot hurt.In this situation, and with most town homes in this part of Houston, we may not need more insulation (the homes are not that old in most instances). Also remember to look at the plenums and the rest of the equipment for cold air. At this point, I should remind the reader of how well a forced air cooling system works. The home was set to 72F, yet our exterior temperatures have been around 95F. AC systems usually can cool the home to 20F lower than the exterior temperature. The homeowner may want to set the thermostat to 76F or 78F and turn on the ceiling fans. Air movement makes us feel cooler. I did not ask, but a programmable thermostat would be a benefit here.
Here is where we have to deviate from the normal home. He has single paned aluminum windows. Awnings, tree, bushes are out. Yet we do have options, which will work in any home, but become something of a must here. Replacing the windows with a double or triple paned window would be great, but this is not cheap. We can take several steps or a combination of the following. A window screen that can block the sun’s heat. Most window screens only cover the window opening area, so have a screen that covers the entire window. There are window film products that still allow a clear view out of the window which block these rays too. Caulk the windows. A caulk seal does not hold forever, so new caulk will be needed. Lastly, a Roman shade or blind. This shade has a honey combed or diamond pattern when you look at it from the side. The pocket of air acts as an insulator. The part facing out towards the window would be white, while the face towards the interior can fit with your room decor.
Over time all wall joints could use a new seal of caulk. You may find that there is not much insulation behind the walls, or at least the insulation around the electrical system components may not have been done well. Place the foam insulation pads made for the cover plates behind each light switch and outlet on an exterior wall. Check weather stripping around doors and windows. Actually, most of this is the same things you would do for any house, so I am going to skip it.
The one problem that comes up with many town homes that I have seen which is different from homes is the outside air conditioning compressor unit. Often these sit on the roof or on a ledge around the second story. Frequently you will find them between two town homes. If the unit is in a position where it is being hit by sunlight for long periods, you may want to consider shading it. Here is the reasoning. The coolant is traveling through the pipes in the compressor shedding its heat, so that cool refrigerant goes back to the evaporator coil. If the compressor is being heated by the sun, it becomes that much harder for the unit to shed its heat. Having a shading fence that gives the foot clearance for air flow can make a big difference. Since town homes are not getting shade from trees, the compressor can be in the same situation. For the units on edges, an awning may be a good option. For roof top units, you may want some type of tent or deck over the unit. You have to see what is allowed in the complex.
Read the other articles, but keep in mind how you can change the information to fit your needs.