Helping you plan furnace/air conditioner upgrades

When a furnace and/or air conditioner needs to be replaced, a home energy audit should be completed first to ensure that your new heating/cooling appliances aren’t oversized (and therefore inefficient and expensive to operate).

How a correct upgrade translates into a lower BTU furnace
– and more savings

It’s common for houses built in the 1950s and 1960s to have an oversized furnace – often 100,000-120,000 BTU. Without upgrades to the building envelope, the correct sizing of a new furnace might be in the range of 80,000-90,000 BTU. However, if the home’s envelope is upgraded with insulation, improved windows, doors and air sealing, the correct size of the furnace may drop to 60,000 BTU, with an actual improvement in comfort.

Avoid the short – cycling cash drain

Installing a new furnace before making your other energy efficiency improvements is unwise. Homeowners often select a large furnace with reserve capacity to heat the house on the coldest of winter days. On normal winter or spring and fall days this will result in ‘short-cycling’, when a furnace does not have sufficient time to reach its steady-state efficiency and thus provide maximum efficiency. A higher output furnace might seem like a good investment, but it could end up burning more of your money than a smaller furnace (suited to your actual home’s heat load) if it short-cycles on a regular basis.

Testing for back-drafting of toxic combustion gases

Replacing a conventional furnace with a high-efficiency (HE) condensing furnace often leads to an ‘orphaned’ hot water heater. As well, many homes have other combustion appliances such as gas or wood fireplaces that vent through chimneys. During your energy audit, a back-draft test is conducted in which all exhaust devices are turned on – range hood, bathroom fans, dryer, and central vacuum, etc. The level of depressurization is measured by the CEA’s blower door equipment. If the pressure differential between inside and outside reaches -5 Pa or higher, the homeowner is advised of the danger of back-drafting deadly combustion gases like carbon monoxide into the house.

Ensuring sufficient ventilation

Some houses may not be getting natural air exchange between inside and outside, but especially after installing a new HE furnace and closing off the existing chimney, the house becomes tighter and you may not be getting enough fresh air. A solution is to install extra ventilation – often by means of a heat recovery ventilator.

Pre-empting the health risks and expenses of excessive humidity

As well as making the house tighter, a new HE furnace can mean increased humidity. Signs of this include ‘sweating’ windows and/or water pooling on windowsills. Wooden windows don’t take long to rot when kept perpetually damp, and will soon need replacing. An energy audit informs homeowners on the recommended number of air changes per hour, and indicates whether current conditions fall below Federal CMHC guidelines. The homeowner is then advised on appropriate measures for optimum air quality.

The GreenSaver Home Energy Audit is normally a two-phase process of systematic testing and reporting performed by our Certified Energy Advisors (CEAs).

STEP 1

The advisor conducts a full review of the external and internal elements of your home that relate to its energy efficiency. This review includes taking photographs of the home as well as various equipment and appliances installed within it.

STEP 2

A blower door test is conducted to measure your home’s air leakage. While the blower door unit is running, the advisor tours the house with the homeowner to identify air leakage penetration sites and advise on possible solutions. The blower door test also reveals any dangerous back-drafting of combustion devices.

STEP 3

Using specialized software, the home is modeled and a full report is prepared and sent to the homeowner. The report emphasizes areas where improvements can be made to the home that will either provide greater comfort or energy savings. These recommendations are generally prioritized, with the upgrades making the largest difference at the top of the list.

Pre- and post- energy audits

Many government-based rebate programs require a preliminary and follow-up audit in order for the homeowner to qualify for reimbursement. In most cases, to be eligible for a rebate the preliminary audit must be completed prior to any upgrade work being done. Here’s how it works:

1. A GreenSaver CEA conducts an initial examination of your home, logging a complete series of energy efficiency measurements
2. You receive a full status report with recommendations for upgrades and their estimated costs
3. You facilitate the recommended upgrades to your home through GreenSaver or a qualified contractor of your choosing
4. Your GreenSaver CEA returns to conduct a second audit to measure/confirm overall energy efficiency gains
5. The above documentation may be used to qualify for various Federal, Provincial or local grant programs. Please refer to the Incentives section of this website or contact GreenSaver for information pertaining to programs currently available in your area.