MR Cool's HVAC FAQ

AB811 is California's 2008 legislation to empower municipalities to fund installation of energy-efficiency upgrades to existing residential, commercial, industrial, or other real property. Municipal bonds are issued by states, cities, and counties, or their agencies (the municipal issuer) to raise funds. With the 2008 passage of the California AB811 bill, California cities and municipalities can help their citizens finance renewable and energy efficiency projects by issuing tax free PACE (Property Assessed Clean Energy) Bonds to pay for initial installation costs.

Repayment is stretched out over the life of the energy generation or conservation addition to the building and is paid back as a line-item on the Home's property taxes. Should the homeowner sell the Property at any point before the loan has been paid in full, the balance would remain with the property and would be declared when the property was being sold. The monthly payment on the loan must not exceed the estimated energy savings of the work being financed.

HVAC stands for Heating, Ventilation, and Air Conditioning. It applies to any system inside a structure that is responsible for moving and/or conditioning the air inside. Your furnace, kitchen hood, bath fans, and even your dryer vent are all part of the HVAC umbrella.

An HVAC System's capacity is measured in BTUs (British Thermal Units) and the efficiency is measured in SEER or more accurately, EER. The heating capacity of a Furnace or Fan Coil is always listed in BTUs and are typcially between 50,000 and 135,000 depending on the size of the air handler. The cooling capacity is also measured in BTUs, but is typically talked about in "tons". A "ton" translates to 12,000 BTUs, so when you hear your HVAC system described as a 4-Ton air conditioner, it means that the condenser has a 48,000 BTU cooling capacity.

SEER, or Seasonal Energy Efficiency Ratio, is the measure of a units efficiency calculated out and averaged across an entire year, taking all seasons equally. EER, or Energy Efficiency Ratio, is measured the same way, however it is only calculated at 95 degrees outside, and therefore is more accurate when predicting the efficiency of an Air Conditioning System in Fresno's climate. In both cases, the higher the number, the greater the efficiency but there is no true unit of measure.

Sizing is a very difficult problem to solve, as it requires many variables to be taken into account. Many factors must be analized: infiltration, ventillation, insulation, window efficiencies, and equipment efficiency. High infiltration means the house, as a box, has a higher load, and would require a larger HVAC system. Similarly, older windows are dramatically less efficient at preventing thermal conduction. Poor wall and attic insulation means your house will gain and lose temperature more rapidly. Leaky ducts in the attic also contribute to the load, as well as location of the air handler, length of duct runs, and even the layout of the house. Ultimately sizing equipment should be left up to a professional that can properly model your home in a Title-24 approved software product to accurately predict the cooling and heating loads.

A home's block load is divided into two loads, a Heating load and a Cooling load. The loads are measured in BTUs required to heat or cool the house to the desired temperature. The higher the load, the larger the capacity required to heat or cool the house to the desired temperature. Outdoor weather conditions are critical to determining the block load of a house or building.

The simple answer: No. In almost every case, your heating load and cooling load will be substantially different. Each of these loads is based on geographical regions of the country and the weather in those regions. In Fresno, the cooling load on a house will be much higher than the heating load, since its never truly cold as it is in places like Denver, Colorado, or the Northeast. Likewise, these places that have freezing winters will always tend to have significantly higher heating loads than cooling loads. Your climate is the most important factor in determining your home's loads.

A dualpack system is a single, self-contained HVAC system, and in the Fresno area, they can be found on rooftops. A split system has all the same parts as a dualpack, but it offers them in individual pieces which can be mixed and matched to acheive efficiencies dualpacks cannot. Building codes recently made changes in our local jurisdictions that meant dualpacks could no longer be installed on rooftops in Fresno, and thus forced the move to split systems. A typical split system installation requires a furnace and indoor coil - which install together, either in the garage, closet, or attic - and pair with a condensing unit which would be installed outside on a side yard out of the way. The two pieces of the system are attached by a linset, which provides a mechanism for the refrigerant to travel between the indoor and outdoor units.