Q. We live in an old 1950's house and currently have central heating, which my husband installed in our home a few years ago. Is it possible to add air conditioning, as well. Can anyone help out with advice or how it would work and what the cost would be? Real answers, please...no trolls!

A. You want to start with what you have that is very familiar to you but you haven't described it enough. Is it a forced hot air system with duct work and is the duct work insulated? If this is the case then the process is to install an "A" coil above the furnace and below the plenum that distributes air to the various ducts. This is connected to a condensate drain, and two refrigeration lines that are also insulated. The refrigeration lines connect to an outside unit called a condenser. The condenser has to have electrical power attached to it. The refrigeration lines must be vacuumed out with a vacuum pump and then the refrigerant has to be transferred to the appropriate levels in the now closed system. The cost for this work will vary depending upon where it is done and the going rate in that location. The cost of the equipment will be more static but depend upon the capacity of the unit and this depends upon the size of the house.

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. How often do you need to service your home air conditioning unit, our house is two years old.

A. Once a year...springtime...

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. I just got the ducts in my house cleaned out to get rid of pet dander and help me breathe better. The air conditioning is running great now and seems cleaner to breathe in. The only problem is that there is a loud humming noise coming from the big vent on the wall. It only comes from this big vent, and does not resonate from any of the vents on the ground. The big vent is not the original big vent; my contractor replaced it after the ducts were cleaned because the old big vent was dirty. My contractor says the noise is a result of the air running so openly now, but I'm having a hard time buying that. I think it is the replacement vent vibrating when the air pushes through it. Any thoughts? I'm pretty sure he threw away the old big vent.

A. Call him back and tell him your not satisfied.Lining the duct with duct insulation should help.I think your right about the vibration.

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. 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. It is 90 degrees in our house and only gets hotter they said they won't come until tomorrow afternoon. I work from home, I have a very ill dog, and these are not suitable living conditions.

A. Generally not. Obtain a court order first, you can not just decide to withhold rent. The dog will not be a legitimate reason in court, a signed lease and your AC being out for more then a couple of weeks will though. That is if the AC is covered in the lease. The next day is certainly not a problem for any reasonable person.