Published by CSA Group in , 96 pages Withdrawn The F Standard is intended to provide architects, home builders, heating and cooling contractors. CAN/CSA F (R). Determining the Required Capacity of Residential Space Heating and Cooling Appliances, Includes Update No. Frs|uljkwhg#pdwhuldo#olfhqvhg#wr#Xqlyhuvlw|#ri#Wrurqwr#e|#Wkrpvrq# Vflhqwlilf/#Lqf1#+zzz1whfkvwuhhw1frp,1##Wklv#frs|#grzqordghg#rq#
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He may be reached at andy buildingknowledge. This will be important in both new and existing homes where energy audits or specific air tightness targets have been verified by site testing. An unintended consequence of using the old CSAFM90 standard when designing HVAC systems for today’s new homes is chronic over-sizing of heating and cooling equipment, as well as over-sizing of air duct delivery systems. The interaction between different types of ventilation systems and air leakage is accounted for.
This can, and does, cause problems for builders. Short cycling also results in decreased mechanical efficiency, and compromises the performance capacity of today’s more efficient heating and cooling equipment. Besides being quieter, and often smaller, “right sized” equipment delivers ambient temperatures which are nearly identical on every floor and in every room. Occupants of these Net Zero houses are raving about the “comfort” of their homes.
Smaller loads with traditional forced air systems require reduced fan capacity. The delivery systems i.
Equipment with optimized controls could be more compact, programmed to operate at peak efficiency over longer cycle times and make use of newer and extremely efficient fan motors and pump controls. The table illustrates the results of applying both the old and new standard to a reference home assumed to have an HRV air tightness xsa approximately 2.
Home BUILDER Canada – THVAC Optimization: Bigger Isn’t Always Better
Depending on a home’s layout, short cycling of HVAC equipment can lead to cold rooms on the second floor, and in rooms over garages with exposed floors. Here is a brief synopsis of the more critical changes.
In the new Standard, recognition of the stack effect warm air rising in a home will mean that the assignment of air leakage heat loss will be a function of the floor level of specific rooms.
In applying the new Standard, designers and mechanical contractors will need to recalibrate old “rules of thumb” for sizing equipment in today’s new homes: Today, we have building codes that require increased insulation values, mechanical efficiencies and air tightness.
Voluntary, market-driven programs like EnergyStar, Built Green and R have provided builders vsa the technology and construction practices needed csw build more comfortable, healthy and efficient homes.
In the old Standard the total heat loss for the building was assigned to individual rooms as a function of the heat loss of that room. Within the industry it’s well known that oversized systems in new energy efficient homes often result in comfort issues for occupants and can lead to homebuyer complaints and warranty claims.
In the last two years, the new Standard has been applied on multiple Net Zero projects across Canada with great success. During the cooling season, the problems change, but include poor thermal circulation and inadequate dehumidification. The new CSA F Standard results in more accurate and potentially lower load calculations that reflect the efficiency improvements in today’s new homes. The mechanical systems also operate at peak efficiency further reducing the cost of operation.
Heat Loss/Gain Software Development for CSA F280 Standard
The calculation method can now accept objective airtightness indicators such as blower door air tightness tests.
The new Standard is caa recognized by the Ontario Building Code as of January 1,and is expected to be referenced in the National Building Code of Canada in the near future.
The U factors and solar heat gain coefficients reported by window manufacturers in their CSA A compliant labeling can be directly put into the calculations now. Over the last 15 years, energy use in new homes has been reduced by nearly 40 per cent.
CAN/CSA-FM90 (R) | Standards Council of Canada – Conseil canadien des normes
Somewhat like putting shoes on a child that are too big, oversized HVAC systems result in homes that run “sloppily” and inefficiently. Finally, the new Standard will allow designers to take credit for the impact of heat recovery ventilation devices employed in a home. In other words, rooms on the first floor of a home will be assigned a greater portion of the air leakage component. In many provinces, a new home built today delivers the energy performance of R homes built in the early s.
The new Standard will result in more accurate and potentially lower load calculations given the efficiency changes in new homes. One very direct consequence of these changes is that heating and cooling loads have dropped substantially in new homes across Canada.
For example, a home with an exhaust-only ventilation system creates a slight negative pressure that changes the leakage patterns in a home and the new standard makes allowance for this. These problems can be avoided by the use of the new CSA F standard. It provides a tremendous opportunity for homebuilders and the HVAC industry to rationalize new mechanical system design.