Let’s face it: Weather-wise, the Washington area is far from paradise. So of all our homes’ gadgets and amenities, the devices we absolutely can’t live without are heating and air-conditioning equipment.

To make sure that your heating and air-conditioning systems work when needed, they must be properly installed and maintained — and you need someone to turn to when problems arise.

Washington Consumers’ Checkbook’s evaluations of area heating and air-conditioning services for quality and price will help you find a competent contractor. Through special arrangement with The Washington Post, you can access Checkbook’s updated ratings of local HVAC services for quality and price free of charge until Feb. 20 at checkbook.org/washingtonpost/hvac.

In Checkbook’s surveys, several companies were rated “superior” for “overall performance” by 90 percent 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 percent or fewer of their surveyed customers. Checkbook also found very big price differences. For example, to replace the control board for a Rheem Classic Series 90 Plus gas furnace, prices ranged from $244 to $1,792. To supply and install an Aprilaire 700A whole-house humidifier, prices ranged from $495 to $1,713.

Comparing prices for repairs is difficult because you’ll first probably need to have a company out to diagnose the problem. Because most companies charge hefty minimum fees just to show up, you’ll probably have to pay something to find out the cost of the repairs.

Before scheduling a repair, ask companies for details on their minimum fees and hourly labor rates. Because most repair work is performed on a time-and-materials basis, you can use this information to get an idea of which companies are likely to be least expensive.

Once a company has diagnosed your problem, it should provide you with a written fixed price to repair it. If the 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 quotes from other companies.

If you need new equipment, it pays to shop around. Ask several companies to prepare written proposals. Although obtaining multiple bids for new equipment will save most consumers thousands of dollars, most don’t bother to do so. 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.

If you are considering buying new equipment, 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, request documentation of how much the new equipment will cut your energy bills, and ask questions. You can calculate your own estimates by using the Energy Department’s Home Energy Saver tool at hes.lbl.gov.

For an illustrative home, Checkbook estimated how energy costs are affected by the purchase of new equipment with varying energy-efficiency ratings and found the following:

●For furnaces, it usually makes sense to pay extra for a more efficient one compared with buying a minimally efficient model. The resulting energy savings from more efficient equipment quickly “pay off” extra purchase costs.

●Because all new central air conditioners are required to be fairly energy efficient, in this area it usually does not make financial sense to pay more for a highly efficient model.

●If you’re replacing both your furnace and air conditioner, consider buying a hybrid system that uses an air-source heat pump backed by an efficient gas furnace, with an annual fuel utilization efficiency (AFUE) rating of 90 or more. Such systems offer low energy costs, but because they cost a lot more up front than standard furnace-A/C combos, it takes longer for their energy savings to offset those extra costs.

●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 $24,000, even after factoring in generous available tax and utility company incentives. But because of their energy savings and long life spans (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.

●Look for energy-saving features such as variable-speed blowers and two-stage burners.

●If you’re planning an addition or seeking to improve heating or cooling conditions for one room or an upper floor, consider getting a ductless system. These units, common in Europe and in hotel rooms, allow you to control temperatures in just one space. Because they use very little electricity and don’t lose a lot of energy transmitting air through ductwork, they are highly energy efficient.

●Investing thousands of extra dollars in ultraefficient equipment makes no sense if your home is drafty or poorly insulated or if you set your thermostat to a tropical temperature during the winter. Before upgrading your equipment, make sure your attic is well-insulated and seal up easy-to-fix leaks. (At Checkbook.org, you’ll find advice on these topics.) 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.

Washington Consumers’ Checkbook magazine and Checkbook.org is a nonprofit organization with a mission to help consumers get the best service and lowest prices. It is supported by consumers and takes no money from the service providers it evaluates. You can access all of Checkbook’s ratings and advice free of charge until Feb. 20 Checkbook.org/WashingtonPost/HVAC.

More from Lifestyle: