Answer: Fifty years is too old, and the heating system is not as energy-efficient as the newer models. At that age, a lot of things can go wrong with heaters, and I know that, despite what people say, most homeowners do not have maintenance agreements with heating contractors nor do they have them maintained regularly.
In addition, having a furnace as well as a gas wall heater might be a waste of energy that can be solved if you get a single heating system sized properly for your house.
Now, to central air. Our summers appear to be getting hotter, no matter what is causing it.
Most houses built since the early 1980s come with central air conditioning systems, and many owners of older homes who squandered their equity in the early part of the last decade on nonsense did have the good sense to add air conditioning when they put in their marble master bathrooms and soaking tubs.
Not only will central air provide comfort, it can lower your utility costs in the long run. Look for a system that is energy-efficient and offers more precise temperature control than window units provide.
And, of course, while it might not add to the value of the house, because so many others have it these days, it will be one less obstacle to a quicker sale.
The fact that your house is just two stories is great, because no matter how well the contractor does his job, it is always tougher - and more expensive - to cool the upper floors of a house than the lower ones.
Because you don't have an attic, however, there is no air space serving as a barrier to the sun beating down on your roof. Your heating contractor will face a challenge keeping the second floor comfortable without killing your budget.
That's my advice. Now, here's what you do. Search the Internet, and look at all the major manufacturers' websites. Then, go to www.energy.gov, the Department of Energy site, and read about the latest products and their level of efficiency. The site also provides some links to how systems are sized for a house.
Find out about the warranties and guarantees each manufacturer provides. The manufacturers' sites should have lists of heating and air conditioning contractors in your area. Call them.
When the contractors come to look, ask them questions and write everything down. Make sure you find out everything, including: how long it will take; material and labor costs; guarantees and warranties offered by both manufacturers and installers; and service-call response, that is, do they handle repairs and maintenance on the units that they sell.
Ask your neighbors about their systems, and pass the names of the contractors you talked to along to them, in case any of them have had experience with these companies.
Frankly, there is not a single heating or cooling system about which I have not received at least one complaint since I started writing this column two decades ago. I also have had problems myself until I found a top-notch contractor.
One more thing. You'll have to decide whether the unheated attached garage should be heated. If you say yes, it needs to be ventilated and insulated properly, including air sealing, so that it doesn't become an energy burden.
That may require an insulation contractor as well as a heating and cooling contractor, or at least someone to conduct an energy test of the garage space.
Do it quickly, however. All heating and cooling contractors are swamped with service calls at this time of year.
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Questions? E-mail Alan J. Heavens at firstname.lastname@example.org or write him at The Inquirer, Box 8263, Philadelphia 19101. Volume prohibits individual replies. He is the author of "Remodeling on the Money" (Kaplan Publishing)