Replacing your home's heating or cooling equipment costs thousands of dollars. Even on cool days, such expenses could make you hot under the collar.

So, it makes sense to maintain your current equipment properly and get good repairs when needed. When you do need new stuff, you'll want to work with a company that offers the best possible advice and prices.

Twin Cities Consumers' Checkbook's evaluations of area heating and air-conditioning services will help you find a competent contractor. Through special arrangement with the Star Tribune, you can access Checkbook's ratings of local HVAC services for quality and price free of charge until Dec. 10 via

In Checkbook's surveys, several companies were rated "superior" for "overall quality" by 90% or more of their surveyed customers. But not all contractors are up to the task. Several scored much lower, receiving such favorable ratings from only 60% or fewer of their surveyed customers.

Checkbook also found very big price differences. For example, to replace the control board for a Rheem gas furnace, our undercover shoppers were quoted prices ranging from $263 to $870. And to replace the dual-run capacitor for a Carrier central air conditioner, prices ranged from $135 to $459.

Comparing prices for repairs is difficult, as you'll first probably need to have a company out to diagnose the problem. Since most companies charge hefty minimum fees just to show up, you'll likely have to pay something to find out the price of the repairs. Before scheduling a repair, ask companies for details on their minimum fees and for their hourly labor rates.

Because most repair work is performed on a time-and-materials basis, you can use this information to get an idea which companies are likely to be least expensive.

Once a company has diagnosed your problem, it should provide you a written fixed price to fix it. If the repair estimate is no more than a few hundred dollars, you may as well have the company go ahead with it immediately. If the estimate exceeds $500 or so, consider getting additional quotes from other companies.

If you need new equipment, shop around. Get several companies to prepare written proposals. Obtaining multiple bids for new equipment will save most consumers thousands of dollars. Differences in designs can affect how quickly and uniformly your system heats and cools your house, how much energy it consumes, how much noise it makes and multiple other issues.

Be skeptical about claims of cost savings from a more energy-efficient system. There may be substantial savings — and there are compelling public-interest reasons to install efficient equipment — but some companies exaggerate to sell new, or more expensive, systems (more efficient equipment costs more money).

Get several companies to make proposals, ask for documentation of how much the new equipment will cut your energy bills and ask questions. You can calculate your own estimates by using the U.S. Department of Energy's Home Energy Saver tool at

For an illustrative home, Checkbook estimated how energy costs are affected by the purchase of new equipment with varying energy-efficiency ratings and found that in this area, because the resulting energy savings and available rebates from utility companies quickly "pay off" the extra cost, it makes sense to pay extra for a highly efficient furnace, compared to buying a minimally efficient 90 AFUE model.

On the other hand, in the Twin Cities area it usually doesn't make financial sense to pay more for a highly energy efficient air conditioner rather than a basic unit.

Ground-source heat pumps provide the lowest annual heating and cooling bills, but these systems are extremely expensive to purchase and install — typically more than $25,000, even after factoring in generous available tax and utility company incentives. But because of the energy savings and long lifespans (about twice those of conventional equipment), it makes financial sense to consider them if you know you'll be in your house for a long time.

Investing thousands of extra dollars in ultra-efficient equipment makes no sense if your home is drafty or poorly insulated, or you set your thermostat to a tropical temp during the winter. Before upgrading your equipment, make sure your attic is well-insulated and seal up easy-to-fix leaks.

The best way to cut home energy costs is the most obvious one: Dial down your thermostat and get and use a programmable thermostat.

Heating and air-conditioning services are likely to push for annual professional maintenance visits, and many will offer a maintenance contract. Such frequent professional service may not be needed if you are diligent about the most important maintenance task: replacing air filters whenever they get dirty.

Whether you need repairs or a new unit, pay with a credit card. If you are dissatisfied with the work, you can dispute the charge with your credit card company.

Twin Cities Consumers' Checkbook magazine and is a nonprofit organization with a mission to help consumers get the best service and lowest prices. Star Tribune readers can access Checkbook's ratings of local HVAC companies free until Dec. 10 at