HC220- residential electric heat Flashcards
during the summer insulation keeps heat _____________________
out
during the winter insulation keeps heat _____________
in
Home insulation material is referred to as _________________________ insulation
thermal
Thermal insulation is avalible as:
-bankets
-rigid and spray foams
-batts
-pouring wool
-blowing wool
-loose wool
Vapour barier is a plastic film that is ___________mils thick. or metal foil which has a high _________ to moisture
-6mils
-resistance
Does spray foam create its own vapour barrier
yes
When homes utilizing a forced-air heatinf method are undergoing a heating cycle, the home tends to have slightly ___________ air pressure relative to the outside atmosphere.
positive.
trapped moisture in vapour barriers can also cause:
-building
-“sick building syndrome” from mold
Vapour barriers prevent __________________ which stops the condensation problem
-air leaks
The vapour barrier is always installed on what side
on the warm side of the insulation
3 methods of satisfying the National Building Code
-6 mil poly film
-is sprayfoam is used, its used as its own vapour barrier.
-metal foils
What does the insulation value R represent
the heat-retaining ability of the insulation.
what does the R value define
-amt of resistance to heat flow through one square foot area of a given material for each one degree fehrenheight temp difference on each side of materieal.
The _____________ the R-value number the _____________- heat retaining ability of the insulation
-higher
-better
What are RSI values and how to convert
-metric equvialent to the imperial R-values.
-converted by multiplying the RSI value by 5.7 (RSI x 5.7)
How to convert to/from RSI values
1.convert to a common unit (mm/inches)
2.multiply/divide by 5.7
what is design temperature
a selected temp used in heat loss calculations
What is outside design temperature
temp of the outside air for the first time at which the heat loss is calculated
Design temp tables give the ____________ outside temp that might occur.
lowest
The design temp difference between the ________________ design temp and the ______________ design temp.
inside
outside
how to find design temp difference and what is it used for
- subtract outside by inside.
- is the actual temp difference is the actual temp difference used in heat loss calculation.
What is conduction
process of heat transfer through a material
What is infiltration
-describes any air leaks into a building from the inside.
2 methods to use to determine rate of infiltration and how is it used.
- “crackage” method.
-requires the estimation of the lineral footage of the cracks and windows and doors and the application of an appropreate factor. - amt of air in the building in meters cubed and assume that much air will infiltrate the building once each hour
what is the U factor used for and how to find.
- figuring heat loss
-found by dividing the sum of the R factors into 1( U= 1 divided by R1+ R2+R3….)
in the U factor the _________ the insulaltion value of the components the ________ the factor
-better
-smaller
Using heat trasfer factor how do you determine heat loss due to conduction
-heat transfered x by the area of exposed surface
When determining heater size what heat requirements for a room must be considered (8)
- area of the room
2.amt of exterior wall
3.wheater the room is over a heated space - if a room is under a heated space
- number and size of windows in the room
6.any doors and their size on exterior walls - infiltration losses (cold air entering through cracks around doors and windows)
8.extra heat must be provided to compensate for heat loss through chimneys.. ect
All heaters must be ________________ to meet CSA specifications
performance certified
what is the rule of thumb for heater sizing
-110 watts per square meter,
-approx 10 watts per square foor
