Rater Skills Table

The following are skills required to pass the E-Star™ Rater Training and Certification course and become a successful Rater. The table also shows which skills are presented in the training course or Rater Manual, or whether a candidate must gain these skills independently, either through experience, outside courses, or home study. The sample questions provided here will help candidates determine what areas to study.

Skill Area	Where Learned	Sample Questions
Mathematics Basic Algebra Calculate areas of complex spaces Calculate volumes of complex spaces Calculate weighted averages	On your own	Calculate the area of the roof in the following drawing. Calculate the volume of the object above. Calculate the weighted average age of a group of people with the following age breakdown. 10% are age 7 13% are age 11 26% are age 17 17% are age 3 the remainder are age 5
Economics Estimate the costs of retrofit options Understand the concepts of cost-effectiveness and payback Suggest cost-effective energy efficiency upgrades to the client Understand the concepts of benefit to cost ratio and present value of energy retrofits as presented on the summary certificate. Prioritize various upgrade options according to cost-effectiveness Understand the use of the home energy rating in obtaining mortgages	Reviewed during checklist training Manual Personal research of contractor costs in your area	A home you inspect has R-11 rockwool in the attic. Will you suggest adding R-19, R-30, R-38 or some other R-value to the attic? How do you know how much to suggest? Which will be a more cost-effective option: 1) Replacing single-glazed windows with double-glazed windows? 2) Iinsulating uninsulated above-grade walls with cellulose insulation. If an air-sealing upgrade costs $300, saves $40/year and lasts 15 years, and a furnace upgrade costs $700, saves $60 a year, and lasts 23 years, which will have the larger benefit-to-cost ratio? (NOTE: E-Star’s computer program will do this complex math for you…) Which would you recommend first: the $300 air-sealing upgrade, the $700 furnace upgrade, or spending $4,500 to replace single-glazed metal windows with low-e vinyl windows?
Occupant Comfort Understand how different heat transfer mechanisms affect occupant comfort Recognize occupant comfort problems and determine potential solutions	Reviewed during input training Manual	The occupant tells you that she feels draft around the single-glazed windows. What are possible causes of this discomfort? What are possible solutions? A homeowner says that their bedroom over a garage is cold. What items would you be checking for during your rating inspection? When working with builders, what design and installation practices would you recommend they follow in order to prevent the above problem from occurring?
Building Science Basics of heat transfer (convection, conduction, radiation) Basics of air and moisture flow in buildings Understand the concepts of R-value and U-value Calculate the average R-value of a system of different materials Understand where heat loss typically occurs in the home Understand the sources of heat gain in the home	Reviewed during checklist training Manual On your own	What heat transfer mechanisms are in effect when a person sits next to a patio glass door when its 10 degrees Fahrenheit outside? Calculate the average R-value of a wall. From outside to inside the wall consists of 0.5" wood siding, 3.5" of fiberglass batt between 2x4" studs 16" o.c., and 0.5" drywall. (Note: the software does this automatically) Name 3 sources of heat gain in a typical house, besides the heating system. What three factors are critical to the formation of mold?
Building Materials - Insulation Recognize different types of insulation found in the field Understand the typical uses of different types of insulation Calculate the R-value of a given thickness of an insulation type Calculate the average R-value of a given space with various thickness and types of insulation Inspect walls, attics, crawlspaces, etc. for insulation	Workshop on building systems and insulation Manual On your own	What types of insulation are commonly found in attics? What is the R-value of a 6.25-inch R-19 fiberglass batt when it’s installed in a 2x6-inch wall cavity? After it’s installed, which insulation product can provide an effective air barrier? What types of insulation can help slow down air leakage but are definitely not air barriers? What is the insulating value of an 8-inch wall in a log home? When inspecting a 3-month-old home, why might you find water vapor within basement insulation? (On the surface of the vinyl facing a solid concrete wall…)
Building Materials - Windows Recognize window glazing and frame types Determine whether a window has a low-e film or a gas fill Understand the effects of films, gas fills, thermal breaks, and glazing layers on building energy use and comfort Determine the U-value of window and frame configurations Understand the solar heat gain coefficient	Workshop on windows and solar exposure Manual	Determine the U-value of a triple-glazed, low-e, argon-filled window with vinyl frame. How can you tell if a window has a low-e film? How does adding a low-e film to a window affect occupant comfort? How can you establish the u-value and SHGC of a window? What U-value and R-value is a reasonable target for production builders along the Front Range? How would your recommendation vary when working with a builder in Summit County? When condensation occurs on windows on cold nights, why does it always start in the lower corners? With a given window, will a homeowner who installs typical window coverings increase or decrease the likelihood of condensation forming on the glass?
Building Construction Recognize building materials encountered in the field Obtain areas, volumes, and energy related information from architectural plans Identify building components (e.g. knee wall, rim joist, stem wall, foundation wall) Identify different foundation types Know Colorado Building Code items related to energy	Workshop on building systems and insulation Manual On your own	Describe a knee wall. Where is the rim joist in a one-story house with a full basement? How much attic insulation does the Colorado Building Code require? (Trick question) What is ‘advanced framing?’ And why could a builder using advanced framing be able to build a home with 2x6-inch framing lumber for the same cost as that of the typical builder who uses 2x4s at 16-inch centers? On the second floor in a typical home, why shouldn’t there be any headers above windows on two of the four exterior walls?
Air Leakage Understand the effects of air leakage on home energy use Use of blower door to determine the air leakage rate in a home Calculate the natural air changes (NACH) from a blower door CFM50 reading Locate cost-effective air scaling opportunities in the house Understand the effect of duct leakage on total air leakage and on home energy use	Optional blower door workshop Manual	A blower door test gave you 2500 CFM50 for a 15,000 ft3 house. It is one story and normally shielded. Find the natural air changes per hour for the house. Using an infrared camera on a 20-degree-F day, you observe that the studs in a kneewall actually look warmer than the insulated cavities between the studs? What could be the reason for this anomaly? The same infrared camera shows the tub and shower in the master bedroom are cold from air leakage. What’s the best way to block that air leakage? Why should this improve the durability of the paint job on the exterior of the master bathroom? Why are homes built over crawlspaces typically 20%-25% leakier than homes built over slabs and basements?
Solar Energy Understand the path of the sun at different times of the year Estimate the effect of various shading devices on solar gain through a home's windows Understand the concept of thermal mass Recognize passive solar strategies Recognize active solar systems	Windows and solar exposure workshop Manual On your own	How far must a horizontal overhang project in order to completely shade a south-facing, 5' vertical window on the summer solstice? Describe the concepts of a passive solar sunspace and a Trombe wall. Is a concrete slab under carpeting effective as thermal mass in a passive solar building?
Fuel and Bills Determine the fuel type(s) used for hot water, heating, and air conditioning systems found in the field Understand the effects of fuel type on the rating Determine the suppliers of fuel in your area Understand and analyze utility bills Understand electricity use of typical home appliances and lights Understand the concept of heat content of different fuels Recognize a utility bill that is higher than average, and determine potential reasons for this	Workshop on heating, ventilation and air conditioning Input training sessions Manual	Determine the monthly average electricity use from a year of utility bills. List some reasons a gas bill of your client might be higher than average. Which appliance is likely to add the most to an electric bill: lights, a refrigerator, or a television? When, where (in Colorado), and under what circumstances might it make at least reasonable economic sense to install a ground-source heat pump in a new Colorado home? Some builders around the country are guaranteeing both comfort and energy consumption for their home-buyers. What keys and factors should one look for in order to make this a viable system, not just a hyped advertisement? Why should you always obtain a 12-month summary of energy consumption and utility costs, from a homeowner, when you visit to rate an existing home?
Mechanical Systems Recognize mechanical system types (e.g. boiler, furnace, heat pump, etc.) Determine mechanical system age and efficiency Perform simple tests on mechanical systems Understand concepts of AFUE, COP, and EF for mechanical systems Recognize when to adjust the manufacturer's stated efficiency of a mechanical system Adjust furnace, boiler, or heat pump efficiencies for defects in the heating plant, plant controls, or distribution system	Workshop on heating, ventilation and air conditioning Checklist training sessions Manual	The house you are rating has a new boiler. The manufacturer states that it has an AFUE of 78%. The pipes are uninsulated and run through the crawlspace. How much should you de-rate the AFUE? Determine the fan off temperature in a furnace. What is the EF of a typical 1995 gas-fired water heater? The average air conditioner installed in Colorado is probably oversized by up to a factor of two. What might be the consequences of this oversizing—on the homeowner and on the utility? What should a builder do to avoid this problem in the future? Why is it that Colorado has perhaps the leakiest ductwork in the nation? What are the three best steps to reducing ductwork leakage in our ductwork in a) new homes, and b) existing homes? Apart from better sealing of ductwork, what are several other steps builders can take to reduce AFUE performance deductions associated with their ductwork? What level of duct insulation is required by the new International Energy Conservation Code for covering ductwork running through unconditioned spaces? Should wall stacks (ducts running up exterior wall cavities) meet this requirement?
Client Interaction Interview the client before the rating Explain rating and upgrade options to the client Provide client consumer disclosure form	Input training Manual	Using the rating output, explain which upgrade measures are cost-effective. What is the best way to determine if a home has a comfort problem?
Checklist Input Fill out the ERHC Checklist Understand definitions Understand the assumptions behind inputs and tailor inputs accordingly Understand input definitions of heated vs. unheated space	Computer input training sessions All workshops Manual	Is the following basement considered heated or unheated space? The furnace is located in the basement. The basement is not intentionally heated. Uninsulated, unsealed ducts run through the basement. The basement ceiling is insulated to R-11.
Rating Output Analyze rating output for the client Understand the point system and how it is affected by energy efficiency improvements Understand the lending implications of the rating	Input training sessions Manual	· Input training sessions · Manual The upgrades suggested raise a home rating from 60 points to 69 points. What does this mean for the client who wants to obtain an energy improvement mortgage? The output shows that the suggested window upgrade has a benefit to cost ratio of 0.4. Explain the implications to the client. How might you use the output of “Tons of CO2 reduced” figure, as listed on the summary rating certificate?