What the Heat Cool Contractor Should Do

The checklist and explanations below will assist you in evaluating the capabilities of different HVAC companies and the proposals they submit. The requirements will help you understand the factors involved in a quality installation.

Have the contractor prepare a load calculation for your home. To install the right size unit, contractors need to know the home’s heating and cooling requirements. These calculations are based on a variety of factors (e.g., size of the home, type of windows, insulation amounts, etc.). Discuss alternatives such as additional insulation that would reduce the unit size required. Discuss alternatives that will reduce operating cost such as additional insulation.

Determining heating/ cooling loads based on the building’s square footage is inaccurate and inadequate. Also, basing replacement equipment on the size of the original system could lead to problems since the original equipment size may have been incorrect.

Determine how much air to deliver to each room will require a room-by-room load calculation.

Review the proposed manufacturers’ performance data with you to demonstrate why the unit you’re buying is the right size.
The load calculation (from Question 1) guides proper equipment selection. A unit that is too big (oversized) may have a higher upfront cost, raise your utility costs, remove less humidity, and fail more quickly.

Furnish documentation that the system will deliver the specified efficiency based on
AHRI certification.
Equipment components which have not been tested by an independent organization or are not designed to work together, may not deliver the promised high efficiency performance.

Review the condition of your duct system with you.
Leaky ducts can cause health problems and waste energy. Discuss the additional capacity needed to compensate for the condition or location of your ducts. Installing a ductless system or insulating the roof may be a better alternative. If the ducts are too small they will cause the HVAC system to use more energy and/or deliver less comfort. Small ducts may also lead to early equipment failure.

Review the condition of your current furnace or boiler venting system.
When fossil fuel is consumed, combustion gases are produced. If these silent threats are not removed by the combustion gas vent system, you could suffer grave health problems. Note: Other gas appliances (e.g., gas clothes dryer, water heater, etc.) also need proper venting.

Measure and document the airflow. (Air Balance Report)
Air is the first word in “air conditioning.” The load calculation will provide the information to determine how much air must be delivered to each room. If the furnace, air conditioner, or heat pump does not have the proper amount of airflow, the unit will waste energy, may create health and safety problems, fail to keep you comfortable, and may cause the unit to fail more quickly.

Measure the refrigerant charge.
If the refrigerant charge is not within tolerance, then the unit cannot deliver the full energy savings and system performance.

Ensure the unit is safe electrically.
The fuses and circuit breakers must be correct for the unit being installed. Sometimes new equipment has different requirements than the system being replaced.

Test the firing rate of the new furnace or boiler.
The contractor needs to measure, and possibly adjust, the firing rate to ensure proper peration.

Test the venting system for the new furnace or boiler.
The contractor needs to verify that all of the combustion gases are vented outside your home.

Test the thermostat.
The contractor needs to ensure that the unit operates properly in all modes and that the thermostat is fully compatible with the new equipment.

If ducts are to be repaired, how will duct leakage be measured after the repairs?
The contractor needs to test to be sure the warm and cool air you are paying for is staying in your home and not escaping into unconditioned spaces. This is especially important when ducts are located in the attic or crawlspace.

Test the amount of air going into each room. (Air Balance Report)
The contractor needs to measure the conditioned air flowing into each room to ensure that each room receives the appropriate amount.

Provide a copy of the installation checklist with a record of all measurements taken during installation.
These benchmark measurements will be used by future technicians to ensure that the equipment continues to perform as it should.

Provide a copy of the owner’s manuals, manufacturer’s warranty, and contractors warranty.
These documents provide valuable information for warranties, future maintenance, or repairs. You should know what the manufacturer and the installing company will do in the event of a problem.

Provide a copy of the recommended maintenance requirements for the new Equipment.
If a maintenance program is offered, it should inform you of the components inspected, time frames for inspection, and other factors involved.

Contractors who enjoy a good reputation have worked very hard to earn it and keep it. References from friends, neighbors, and the Better Business Bureau are indicators that the contractor will say what he does, and does what he says. A list of references is a good sign. Call them!

Contractors should provide proof of applicable business documents:
City Permits
Mechanical license
Business license
Insurance, Workers Compensation, general Liability and Auto.
Professional memberships

Load calculation: Building load calculations consider a variety of issues: location (El Paso’s weather is different than that of Houston), orientation (southwest glass gets much more sun than north glass), construction materials (R value of insulation, brick or siding, etc.), building size, etc.

Heating and cooling needs are expressed in British Thermal Units per hour or Btu/h. A “block load” looks at the whole building’s requirements as one large room. A “room-by-room” load calculation refines the calculation to determine individual room’s or zone’s requirements.

Unit Size: A “ton” of air conditioning refers to capacity in relation to melting one ton of ice in 24 hours. The capacity is measured in British Thermal Units (Btu); 288,000 Btu are required to melt one ton of ice in 24-hours (or 12,000 Btu/hr). A 2-ton air conditioner has a nominal capacity of about 24,000 Btu/h.

Manufacturer’s performance data: This is information provided by the manufacturer to specify the capacity for a particular model. You may hear cooling terms like 2-ton or 3.5-ton. These are nominal capacities at standard rating points. For heating systems, the Btu/h are expressed by how much heating capacity goes into the furnace (i.e., an 80% efficient, 100,000 Btu/h input furnace receives enough fuel to create 80,000 Btu/h of output heat).

Equipment selection: Equipment is manufactured to meet standardized performance requirements. Manufacturers publish expanded performance data that details how the equipment performs at actual operating conditions. Applying the manufacturer’s performance data to your home’s load is essential to saving energy with the right unit.

Efficiency: Performance descriptors for cooling are Seasonal Energy Efficiency Ratio (SEER) and Energy Efficiency Ration (EER). Heating application descriptors are Coefficient of Performance (COP) and Heating Seasonal Performance Factor (HSPF). These are determined under laboratory conditions.

Certified matched system: The Air Conditioning, Heating, and Refrigeration Institute (AHRI; www.ahrinet.org) puts heating and cooling equipment through rigorous certification processes to ensure systems deliver the promised performance at certain test conditions.

Combustion analysis: When fossil fuels are used to heat a home, furnaces and boilers should be adjusted to ensure that they are efficiently consuming fuel and that they have sufficient oxygen to properly combust the fuel. A combustion analysis test, with a properly calibrated meter, is an optimal approach to verify the combustion rate.

Vent system: When fossil fuels are used to heat a home they produce carbon monoxide (CO). Your contractor will verify that the vent piping is the correct size and properly installed. A CO test is supplemental to ensure that the furnace or boiler is venting properly, exhausting all of the harmful gases away from the occupants.