FC Load Calculations & Equipment Sizing 3

Question 1

Which building characteristic most significantly increases heating load in cold climates?

Accepted Answer

Exterior wall area with low insulation R-value

Answer

Exterior walls with low R-value insulation are major sources of conductive heat loss, significantly increasing the heating load in cold climates.

Question 2

What is the effect of a slab-on-grade foundation on a home's heating load compared to a basement?

Accepted Answer

Slab-on-grade can increase perimeter heat loss if not properly insulated

Answer

Slab-on-grade foundations can experience significant perimeter heat loss to the cold ground and exterior, increasing heating load if the slab edges are not insulated.

Question 3

What does 'internal heat gain' refer to in a load calculation?

Accepted Answer

Heat generated by occupants, appliances, and lighting within the conditioned space

Answer

Internal heat gains are heat produced within the conditioned space by people, lighting, and appliances, which can offset part of the heating load in winter.

Question 4

A technician is sizing a furnace for a 2,000 sq ft home in a cold climate with a calculated load of 35 BTU/h per square foot. What is the approximate total heating load?

Accepted Answer

70,000 BTU/h

Answer

Multiplying the floor area (2,000 sq ft) by the heat loss rate (35 BTU/h per sq ft) gives a total heating load of 70,000 BTU/h.

Question 5

Why is using a simple 'rules of thumb' (e.g., BTU per square foot) discouraged as the sole method for sizing furnace equipment?

Accepted Answer

Rules of thumb ignore critical variables like insulation, windows, and climate, leading to inaccurate sizing

Answer

Rules of thumb ignore critical building-specific factors such as insulation levels, window area, orientation, infiltration, and local climate, which can lead to significantly over- or under-sized equipment.

(FC) Furnace Installation and Maintenance Certification Practice Test

(FC) Furnace Installation and Maintenance Certification Practice Test

FC Load Calculations & Equipment Sizing 3