What HVAC maintenance can you do yourself, and what needs a pro?
Updated · KeystoneProGuide editorial team
Which HVAC jobs can a homeowner do?
A short list, and it matters more than it looks: the filter, the thermostat, the carbon monoxide alarms, and keeping vents and equipment clear. ENERGY STAR's maintenance checklist gives exactly one job to the homeowner, inspecting, cleaning or changing the filter once a month, and says your contractor can show you how. Everything on the rest of its list is for the contractor's yearly visit.
How should you handle the filter?
Look at it monthly, especially in winter and summer. ENERGY STAR says to change it if it looks dirty after a month and at least every 3 months. A dirty filter can raise energy costs and damage the equipment, leading to early failure.
If you want a better filter, the U.S. Environmental Protection Agency's advice is specific. MERV ratings show how well a filter captures particles between 0.3 and 10 microns, and the higher the number, the better it traps them. The EPA suggests choosing at least MERV 13, or as high a rating as your system fan and filter slot can take, and says you may need an HVAC technician to tell you what your system can handle. All filters need replacing on schedule.
Keep expectations modest. The EPA says the most effective ways to improve indoor air are to remove the sources of pollution and to ventilate, and that HVAC filters can reduce indoor air pollution but cannot remove all pollutants.
What can you do with the thermostat?
Set it well and leave the rest to the equipment. ENERGY STAR's advice differs by system:
- Heat pumps. Pick a comfortable temperature and leave it. Unlike a furnace or boiler, a heat pump does not save energy by being turned down while you are out or asleep. Avoid the "Auto" mode that switches between heating and cooling, and use the auto fan setting or the lowest fan speed that keeps you comfortable. If you have both a heat pump and a furnace, ENERGY STAR says to use the heat pump year-round.
- Furnaces and boilers. Setting the temperature back when the house is empty or everyone is asleep is where a programmable or smart thermostat earns its keep.
- Replacing the thermostat. If you buy a smart thermostat, ENERGY STAR says to make sure it is compatible with your system, and that very high-efficiency equipment may need the manufacturer's own controller.
What safety jobs belong to the homeowner?
- Carbon monoxide alarms. The CPSC recommends battery or battery-backup alarms on every level of the home and outside sleeping areas, not in kitchens or above fuel-burning appliances and not near heating vents. The test button checks the circuitry, not the sensor, so replace alarms at the age the maker gives; the CDC says to follow the manufacturer's instructions or replace them every 5 years, and to check batteries when the clocks change in spring and fall.
- Clear vents. During renovations, the CPSC says to make sure appliance vents and chimneys are not blocked by tarps or debris, and that appliances work properly when the work is done.
- Outdoor units. The condenser coil is on ENERGY STAR's list of things the contractor cleans at the spring visit, because dirty coils make the system run longer.
What should you leave to a professional?
Anything that burns fuel. The CPSC says never to service fuel-burning appliances without the proper knowledge, skill and tools, and to use the owner's manual for minor adjustments only. It says most appliances should be installed by qualified professionals and the heating system inspected and serviced yearly. The gas and oil connections, burner and heat exchanger checks on ENERGY STAR's list are this kind of work; it warns that faulty gas or oil connections are a fire hazard and can contribute to health problems.
Anything involving refrigerant. Federal rules require Section 608 certification for anyone who connects gauges to measure pressure or adds or removes refrigerant. The EPA also prohibits intentionally venting refrigerant while servicing or disposing of air-conditioning equipment. Unless you hold that certification, adding refrigerant to your own air conditioner is not allowed.
A gas leak. If you smell gas, the utility's advice, as Philadelphia Gas Works puts it, is to leave, call from a safe place, and not try to shut off valves or appliances yourself.
Electrical work inside the unit. ENERGY STAR's checklist has the contractor tighten connections and measure voltage and current on motors, and says faulty connections can cause unsafe operation.
Can a homeowner replace a furnace or air conditioner?
Not realistically. Whoever does it, the work needs a permit: Pennsylvania's construction code regulation says an owner or authorized agent who intends to install or replace a gas or mechanical system must first apply for a permit. In Philadelphia the city's mechanical permit requires a licensed contractor to perform the work. Add the refrigerant certification rule and the CPSC's advice that most appliances be installed by qualified professionals, and a replacement is a job to hire out.
The yearly service schedule is in how often to service your HVAC system, and what the contractor should check is in what to expect from an HVAC visit. Contractors are listed on the HVAC contractors directory page.
Sources
- Maintenance Checklist, ENERGY STAR
- Heat & Cool Efficiently, ENERGY STAR
- What is a MERV rating?, U.S. Environmental Protection Agency
- Air Cleaners and Air Filters in the Home, U.S. Environmental Protection Agency
- Air-Source Heat Pumps, ENERGY STAR
- Smart Thermostats, ENERGY STAR
- Carbon Monoxide Fact Sheet, U.S. Consumer Product Safety Commission
- Carbon Monoxide (CO) Poisoning Basics, Centers for Disease Control and Prevention
- Section 608 Technician Certification Requirements, U.S. Environmental Protection Agency
- Stationary Refrigeration - Prohibition on Venting Refrigerants, U.S. Environmental Protection Agency
- Natural Gas Safety, Philadelphia Gas Works (PGW)
- 34 Pa. Code § 403.62. Permit requirements and exemptions., Commonwealth of Pennsylvania (Pennsylvania Code)
- Get a Mechanical Permit, City of Philadelphia