Hughes Air is here to help with all your HVAC troubleshooting needs. You may have a tripped circuit breaker. Recommended Action: Check your home circuit breaker box and reset circuit breaker. Your thermostat/control may be off or set incorrectly. Recommended Action: Check to make sure your thermostat/control is on and set to cool. Reset to your desired temperature. Your indoor unit is running but the outdoor unit is not. Recommended Action: Air coming through your vent will be warm. Check temperature setting on thermostat/control. If no change, contact . In the meantime, try turning off your thermostat/control for 1 to 3 hours to see if it will reset itself. Your gas could be turned off. Recommended Action: Check gas valve at gas company meter, check shutoff valve at furnace and check for other shutoff valves. Contact the gas company to have gas valve turned on or contact . Your system could be turned off or your unit unplugged. Recommended Action: Check your thermostat and heating unit to assure that they are both plugged in.

Refer to your use and care guide or contact . Your thermostat may be off or set incorrectly. Recommended Action: Make sure your thermostat is on and set to heat. If thermostat is on, reset thermostat to your desired temperature. You may have dirty filters. Recommended Action: Check the filters in each of your system’s components. Clean or replace filters as recommended in your use and care guide. If problem persists, please contact . Your system may have frozen up due to a dirty coil. Recommended Action: Check for signs of water below unit and cold exterior surface of indoor coil enclosure. In the meantime, try turning your thermostat off for 1 to 3 hours to see if it will defrost. If your system is reaching its set point, is it working correctly? Have your local temperatures been extreme lately? Recommended Action: Check the following: Is your system cycling constantly? Is your thermostat reaching its set value? Do you have any new appliances (e.g., a hot tub or pool heater) that use lots of power?

Have you checked to see if your local utility company had a recent rate increase? If your system is not reaching its set point, please contact . Your system could be trying to reach a set point that is too extreme. Recommended Action: Check the set point on your thermostat. Is it very low (in summer months) or very high (in winter months)? First, reset your thermostat. If that doesn’t work, please contact . The overflow switch is probably not working Recommended Action: Turn off your system and contact . Check any of the above troubleshooting issues for help. Recommended Action: If none of the troubleshooting answers address your problem, then turn off your system and contact .Recently I ran a guest post here in the Energy Vanguard Blog by Ted Kidd, who argued against thermostat setbacks, saying they don't save energy anymore. His reasons were flawed and his car analogy misleading. Setting back your thermostat when you're away or at night definitely can save energy (depending on a few factors, as noted below).

Although he said a lot and said it forcefully, Kidd is dead wrong on this issue. Two simple and definitive reasons stand in his way: Physics and studies of energy savings from thermostat setbacks. Let's take a look at each of them. As I wrote here recently, your HVAC system is like a faucet and your building envelope like a cup. The leakier your cup is, the more you have to open up the faucet. One thing I didn't write in that article is that is that the leakiness of your cup depends on the temperature difference between inside and out. kenmore ac unit searsIn the world of physics and building science, we call that temperature difference ΔT (pronounced delta T).window ac units 10000 btu hr In another post, I wrote about heat flow and showed the basic equation for heat loss or gain through the building envelope in a home:car air conditioning repair jackson ms

Let's focus on winter because that's when most homes have the biggest temperature differences. I ran some simple calculations using this equation for two scenarios. In both cases, the house has a total UA equal to 300. (UA is the product of U-value, which is the reciprocal of R-value, and the area.) In both cases, I'll use 30° F as the outdoor temperature. In this scenario, we'll do as Kidd suggests and leave the thermostat at the normal setting. Let's take 70° F as the indoor temperature (despite the strange geography of thermostat setoints showing that Texans are likely to use that setpoint whereas Vermonters live with a cool 63° F setpoint). That gives us a ΔT of 40° F. Using a time period of 8 hours, since Kidd discussed a setback of 8° F for 8 hours, we get a total heat loss of: Total heat loss = 96,000 Btu That's the amount of heat the home loses if through the walls, floors, and ceilings if we leave the thermostat alone. Yes, this is a simplification that ignores othe forms of heat loss and the heat gains inside the home, but it gets at the heart of why setbacks work.

Now, let's look at the same house (UA = 300) in the same outdoor conditions (30° F outside) and set the thermostat back 8° F for 8 hours. Since our heat loss equation is linear and 8 is 20% of 40, we would see a 20% reduction in the heat loss during that period if the temperature dropped those 8° F immediately. Instead, let's make it a bit more realistic and say that it takes 2 hours for the temperature to drop those 8° F. That means our ΔT doesn't get to 32° F until the third hour so in this case we'd have 2 hours with ΔT between 40° F and 32° F and then 6 hours with ΔT = 32° F. I made it simple and assumed a steady temperature decrease rate of 4° F per hour, so here are the numbers: Adding up the total amount of heat loss in the far right column, we find: Total heat loss = 79,200 Btu This number is 18% less than the 96,000 Btu of heat loss when you leave the thermostat alone. This bit of basic physics yields a simple result: Lowering the ΔT reduces heat loss.

Well, actually we didn't need to run any numbers to show that because the equation shows it all by itself, but it's instructive to see how some sample numbers work out, I think. So, setting back the thermostat and letting the house temperature get closer to the outdoor temperature reduces heat loss or gain through the building envelope. The reduction is proportional to the ΔT. Your heating system has to supply an amount of heat equal to what the home is losing. Yes, real homes behave in more complex ways than my calculations allow for, but the above scenarios capture the basic physics involved. To verify that this actually happens in homes, all I really need to say is: Michael Blasnik has done multiple studies and found that thermostat setbacks save energy and money. In case you don't recognize the name, Michael Blasnik is your go-to guy when you need residential energy data. I wrote a couple articles about a big study he did with Advanced Energy in 2009 (one on REM/Rate and another on radiant barriers).

He's been in this field as long as I might've been had I figured out what I wanted to do right after college (early '80s) and he knows his stuff. I mean, he really, really knows his stuff. The table below shows the results of 7 studies that he conducted for a gas utility company in the northeast US (first 7 rows) and one study done by another group (RLW Analytics, last row). As you can see, the savings are significant, and these numbers are the incremental savings. That is, they're the savings that can be attributed to that measure only after accounting for the effects of the other measures taken to improve the homes in the studies. The percent savings range from 5.0% to 8.2%. In addition to Michael Blasnik's work, there are plenty of other studies available, and Canadian engineer Robert Bean, has compiled a list of 22 of them. Check out his comments about programmable thermostats preceding the list on the Healthy Heating website. I like to consider new information and question what I think I know about the world.

When warranted, I'll change my views to incorporate the new information and replace old views. The introduction of the Nest Learning Thermostat last fall gave me a chance to look at the argument against using thermostat setbacks, since Kidd put it out there so forcefully. Yes, it's true you have to consider the equipment because if recovering from a thermostat setback means that your heat pump kicks the electric resistance heat on, your bill may be higher. Right-sized heating and cooling equipment and equipment that can adjust its capacity to meet the loads also impact the effectiveness of setbacks. So does a lot of thermal mass in homes (though most furniture doesn't have a lot of thermal mass). Is it possible that setbacks won't save money for you? The title of this article refers to the general case, though, and for a great many homes, thermostat setbacks can save energy. My first reaction to people who say that thermostat setbacks don't work has been to say that they need to go back and study the basic physics of heat transfer.