Q. I replaced a fully functional home thermostat with a new digital thermostat from Honeywell. Now neither my heating nor my air conditioning works. I have 5 wires white (W), red (R), green (G), blue (C) and yellow (Y). When I cross a wire with red nothing powers up, so its not the thermostat: for example, crossing red with white should turn on the heating. My breaker box shows all the breakers are enabled. I see no breakers or switches on or near the heating or air conditioning units. I've also reset all the GFCI outlets. What could I be missing? I hate to have to call an HVAC expert out here to kick a breaker or something silly. This has to be something simple. HELP!! More... The furnace is in the attic; Its difficult to work with. I prefer to test with the air conditioning that is just outside the door. Tests for just the furnace don't seem to explain why the air conditioning does not work either. Much more... The house was built in 2004. Much much more... I found the furnace documentation nailed to a 2x4 in the attic; actually its more of a crawl space: a real pain and dangerous to get to and move around. Yes, I was incorrect, all wiring for the air conditioner (AC) appears to go through the furnace, so I can not just test the AC. I now believe that I was working with a live wire (R); I tuned off breakers marked "AC", but there is no breaker or breakers marked "Furnace". Based on the documentation, its likely I blew out the fuse on the furnace circuit board, a 3 amp, 32 vac fuse. I will go buy a new fuse today and climb up into the attic tonight to change it out. Thanks for the hints on the fuse; I'll look around for another breaker box too. Conclusion.... I picked up a fuse at the local auto part store; Home Depot didn't carry the type specified by manufacturer. Once I figured out how to open the second part of the door, there was the purple fuse. I pulled it and saw that it was burned out. I replaced it, went down to the new thermostat and started-up the furnace. A whole lot of drama for a 50-cent fuse. Thanks everyone!

A. Open up your furnace and see what wires go where. The R and W on the board are for heat, but they don't always set it up colour coded like that. Check for an auto style fuse on the board, usually a 3 or 5 amp (purple or yellow). You may have blown that if you put the C (common 24 volt) wire in the wrong place or crossed it with something else. Add on: If your fuse in the furnace is blown, it won't relay the signal to the AC. Nothing will work. You have to check it. If you didn't power down the furnace while replacing the stat, chances are you crossed the 24 volt with something and popped it. The thermostat does not need 24 v to work if it has batteries in it, and a furnace from 2004 will more than likely NOT burn out the transformer. The transformer will pretty much out last any other component in a furnace.

Q. Unit is only 5 yrs. old, not sure if I'm quoting right I had about 5lbs. of pressure they took it up to 60-70 I believe.

A. Average range $175- $250. unless there is a leak on the line. than it's more.

Q. The recent problem seems to be related to the outdoor cooling fan. The air conditioning system seems to be working properly, but there is a loss of cooling of the air coming from the indoor air conditioning vents. I inspected the outside unit, and yesterday the cooling fan was stopped with a humming/grinding sound. The capacitor looked good (no bulging), but I'm not an electrician and I have no way (or the knowledge) to test voltages and amperages and such. Anyway, I blew on some dust/dirt/cobwebs around some of the wires, and started the system back on and the fan moved at normal speed and the system worked and cooler air came out. However, today, the indoor temperature wasn't maintained and I went outside and the cooling fan was running much slower (but it was running). After I turned off the system, I felt the metal cover of the outside unit, and it was very hot, and it seemed that the source of the heat came from directly above the cooling fan motor. Please contact me!

A. Replace your outdoor fan and while your at it replace the capacitor and everything will be fine. But turn your unit off untill you get it fixed or you'll be changing a compressor or buying a new unit.

Q. The central air conditioning in my apartment is getting repaired and won't be working for 4 or 5 days. I want to improvise something. Maybe taking a fan and pointing it a a bag of ice. Heck.. I don't know... Any tips ?

A. Use the principle of evaporation. Depending on the humidity, it can work wonders. Lightly soak and wring out a sheet before bed, and have a fan blow across you. You will be comfortable enough to get to sleep. Some people get a large amount of ice, put it in a shallow pan, and have a fan blow over it. Another is to fill an ice chest with 70% ice and 30% water, take a hand towels, soak and wring out, then place over head and breathe the cold air. Do it once more but this time leave on your wrists for a couple of minutes. As for a whole house fix, there is no other DIY method I know of. The ice cold towel on the head is really amazing relief even though temporary.

Q. Please excuse my ignorance, but is there a portable air conditioning unit (blows out COOL AIR in a HOT ROOM) without being attached/fixed to the wall, as in carry it with you just plug it in to a wall socket and have it blow out cool air. I know this may seem like a dumb question, but a simple answer would be much appreciated. Thank you!

A. There are two units that are kind of like that, but not quite. one is called a swamp cooler. they evaporate water to absorb thermal energy in a room, but make the room more humid, and only really work in dry climates. however, they are relatively cheap to buy and use little energy. the other is a regular AC unit, but, this is not a window unit. they make one that is a free standing floor unit that can be pushed around and plugged in anywhere. however, the only downside is that there is a 3 or 4 Inch diameter hose that comes out of the back of the unit that must be run outside, through a window or a cat door or something. the unit is similar to window units in that it must move the heat from the room to the outside, but it does not have to hang out the window. they are about as expensive as regular window units. and are much more portable. you just have to point the hose outside. just remember, the heat has to go somewhere. it is very hard to just make it disappear (like an endothermic reaction, a reaction that takes heat)

Q. If you know someone that has and operates their own company, not a big company where you have to wait on hold when you call them i'm adding some rooms in my house and need some bids for the a/c thanks

A. Honest Air i dont have the number but you can find it online good luck

Q. Well my air conditioning broke and we had some people fix it and then it broke again... every time i want it to go to a certain temperature like 75 or 74 it wont move it will stay at like 88 and the 80's and i dont have the number to my ac guy and how could i fix it... i have a digital ac thermometer thing. no the outdoor fan is not runnining

A. Don't take this personally, but if you use phrases like "digital ac thermometer thing" then you aren't qualified to repair an air conditioner. You can check simple things like the circuit breaker. But if it is tripped, it is usually for a reason. And if it trips multiple times, there definitely is a problem. If you aren't satisfied with the last co. Try another one. There are lots of companies in the yellow pages. Or ask a friend or neighbor if they know someone they can recommend.

Q. What is it, and they claim that it can cut air conditioning costs by upto 50% where can i find such contractors

A. There are some cold roofing that is available to make sure the roofing is not only NOT leaking but also it reflects a lot of heat back( if you are in a tropical climate) or act as insulator if you are arctic climate. there are many types roofings that you can do . you can google them, or check the site, you can at least get some basic information on what to expect.