Question 1

The design heating load of a building is an estimate of the rate at which a building loses heat during the near minimum outdoor temperature.

Accepted Answer

The design heating load represents the amount of heat needed to maintain a comfortable temperature inside the building during the coldest temperature of the year. It is based on the building's insulation, orientation, size, and other factors that affect heat loss.

Question 2

The number of heating degree days that accumulate in a 24-hr.period is the difference between 72 F and the average outdoor air temperature during that period.

Accepted Answer

The formula for calculating heating degree days is correct, but it is not necessarily limited to a 24-hour period. It is typically calculated for longer periods of time, such as a month or a heating season.

Question 3

Many residential and commercial buildings have concrete floor slabs rather than crawl spaces or full basements.Downward heat losses are relatively small from interior areas of the floor slab.

Accepted Answer

Concrete floor slabs provide a thermal mass that helps to regulate indoor temperature and downward heat losses from interior areas of the floor slab are relatively small.

Question 4

The proper approach is to perform a heat load calculation ____.

Accepted Answer

Performing a heat load calculation for each room will provide a more accurate and efficient heating and cooling system design. Factoring in seasonal requirements and the owner's usage can also be important, but starting with an individual room calculation is the best approach. Calculating the heat load for the entire building may not account for variations in each room's requirements.

Question 5

Heat flow from a basement or slab-on-grade foundation is determined by complex interactions between the building, the surrounding soil, insulation materials (if present), and the ____.

Accepted Answer

Air temperature above grade is a major factor in heat flow from a basement or slab-on-grade foundation.

Question 6

Knowing how many MMBtu a building requires over a typical heating season is not of much use to most owners.

Accepted Answer

Knowing the total MMBtu required over a heating season does not provide actionable information for most building owners. They need more specific information on how to reduce energy consumption and costs, such as identifying energy efficiency upgrades or implementing energy management strategies.

Question 7

The R-value of a material is not directly proportional to its thickness.

Accepted Answer

The R-value, which measures a material's thermal resistance, generally increases with the thickness of the material. A thicker material provides greater resistance to heat flow, thus having a higher R-value.

Question 8

Heat is lost through all building surfaces that separate heated space from unheated space.

Accepted Answer

This is a basic principle of building science - heat will naturally flow from warmer areas to cooler areas. Therefore, heat will transfer from the interior of a building to the exterior environment through walls, roofs, floors, and windows.

Question 9

All building surfaces that separate heated space from unheated space.(walls, windows, ceilings, doors, foundation, etc.) are called the ____ of the building.

Accepted Answer

The term "thermal envelope" refers to all building surfaces that separate heated space from unheated space, including walls, windows, ceilings, doors, foundation, etc. This envelope is what allows a building to maintain a comfortable temperature and reduces the need for energy consumption. Therefore, option A is the correct answer. Option B is incorrect because heat load variables refer to the factors that affect the amount of heat needed to maintain a comfortable temperature inside a building. Option C is incorrect because "resistance factors" are comprehensive and could refer to many things, not just the building's surfaces. Option D is not a commonly used term in the field of building construction and energy efficiency.

Question 10

It is relatively easy to assess the location and magnitude of all the air leakage paths in a typical building.

Accepted Answer

It is not easy to assess the location and magnitude of all the air leakage paths in a typical building as it can be influenced by various factors such as building design, construction quality, weather conditions, and indoor activities. A professional blower door test is often required to accurately identify and measure air leakage paths.

Question 11

The heating load is ____ of heat flow from the building to the outside air.

Accepted Answer

The heating load is the rate of heat flow from the building to the outside air, typically measured in units such as BTU/hr or kW.

Question 12

A boiler, furnace, or small space heater operating on the same fuel, at the same assumed conversion efficiency, would produce the same estimated annual heating cost.

Accepted Answer

As long as they are operating on the same fuel and assumed conversion efficiency, their estimated annual heating cost would be the same.

Question 13

Once the____ price of the fuel options has been calculated, a simple multiplication determines the estimated seasonal heating cost in dollars.

Accepted Answer

The phrase "unit price" refers to the cost of a single unit of a given commodity, in this case, a unit of the particular fuel option being considered. Once this unit price has been determined, it can be multiplied by the estimated amount of fuel needed during the season to arrive at an estimated total cost.

Question 14

The U-value of any material or assembly is simply the reciprocal of the ____ of that material or assembly.

Accepted Answer

The U-value and R-value are inversely related, meaning that the higher the R-value, the lower the U-value. The U-value represents the measure of the heat transfer through a material or assembly, while the R-value represents the resistance to heat transfer. Therefore, the reciprocal of the R-value gives the U-value.

Question 15

The U-value of any material or assembly is simply the reciprocal of the R-value of that material or assembly.

Accepted Answer

The U-value measures how well a material allows heat to pass through it, while the R-value measures how well a material resists the flow of heat. Since these are inverse properties, the U-value is indeed the reciprocal of the R-value.

Question 16

To estimate the annual space heating cost provided by an electrically operated heat pump, its average COP must be factored in.What does COP stand for?

Accepted Answer

COP stands for coefficient of performance, which is a measure of how efficiently a heat pump can convert electricity into heat energy. It is calculated by dividing the heat output by the electrical input. By factoring in the COP, one can estimate the annual space heating cost provided by an electrically operated heat pump.

Question 17

One common method of factoring local weather conditions into estimates of heating energy use is based on heating ____.

Accepted Answer

Degree days are a measure of the difference between the average temperature outside and a baseline temperature (usually 65°F) which is used to estimate the amount of energy required to heat a building. By factoring in local weather conditions in terms of degree days, more accurate estimates of heating energy use can be made.

Question 18

An object's thermal ____ can be defined as its thickness in the direction of heat flow divided by its thermal conductivity.

Accepted Answer

Thermal resistance is the property of the object which opposes the flow of heat through it. It can be defined as thickness in the direction of heat flow divided by thermal conductivity.

Question 19

One can assume that individual room heating loads are proportional to room floor area.

Accepted Answer

Heating load depends on various factors including insulation quality, window size and type, external wall area, and room orientation, not just the floor area.

Question 20

In addition to conduction losses, heat is also carried out of buildings by uncontrolled air leakage.This is called ____ heat loss.

Accepted Answer

Uncontrolled air leakage is also known as infiltration.

Quiz 2: Heating Load Estimates