Chapter 7
Estimating Plumbing, HVAC, and
Electrical Work
Introduction
• Estimates of large and/or complicated projects are
prepared by specialists in these trades.
• The ability to compile a takeoff of plumbing, HVAC,
and electrical work can also be a useful skill for the
builder’s estimator who sometimes needs to put
together a quick price for these trades on a small
job.
• Also, some builders like to develop their own cost
estimate for each trade’s scope of work to ensure
that the quotes received are reasonable.
Measuring Generally
• Little information about the plumbing, HVAC, and
electrical systems is shown on the project plans of
small jobs.
• The estimator may need to draw sketches to be able
to assess the layout of systems for a house.
• These sketches can then help the estimator
evaluate measurements such as the length of pipes
for water supply and sewers on the job.
Measuring Plumbing (1 of 3)
• Connecting water lines to main are enumerated.
• Water and sewer pipes are described and
measured separately in linear feet.
• Fittings and valves are described and
enumerated.
• Hangers and supports are described and
enumerated.
Measuring Plumbing (2 of 3)
• Fixtures and equipment are described and
enumerated, including:
–
–
–
–
–
–
–
–
Water meters
Gas meters
Water heaters
Lavatory basins
Water closets
Sinks
Laundry tubs
Bath tubs
Measuring Plumbing (3 of 3)
• Items supplied by the builder and installed by the plumber are
described and enumerated separately, including:
– Refrigerators
– Garbage disposal equipment
– Dishwashers
• Gas line piping is described and measured in linear feet.
• Permits for the work are described and enumerated.
• Pipe insulation is described and measured in linear feet.
• Cutting, drilling, and patching required for this work are described
and enumerated.
Measuring HVAC Work (1 of 2)
• Ductwork is described stating the size and it is measured in
linear feet.
• Range, cooktop, laundry, and bath venting are described stating
the size and it is measured in linear feet.
• Fittings, hangers, and sleeve frames are described and
enumerated.
• Mechanical equipment is described and enumerated, including:
– Air handling units
– Furnaces
– Heat exchangers
– Etc.
Measuring HVAC Work (2 of 2)
•
•
•
•
•
•
•
Control wiring is described and measured in linear feet.
Low voltage wiring is described and measured in linear feet.
Electric and electronic controls are described and enumerated.
Testing and balancing are each measured as items.
Permits for the work are described and enumerated.
Duct insulation is described and measured in square feet.
Cutting, drilling, and patching required for this work are described
and enumerated.
• Cleanup resulting from this work is measured as an item.
Measuring Electrical Work (1 of 2)
• Wire, cable, and conduits are described and measured in linear
feet.
• Cable tray and bus duct systems are described and measured in
linear feet.
• Hangers, sleeves, and supports are described and enumerated.
• Electrical equipment, fittings, and fixtures are described and
enumerated, including:
– Fire alarm systems
– Security systems
– Communication systems
– Etc.
Measuring Electrical Work (2 of 2)
•
Installing appliances is described and enumerated, including:
–
–
–
–
•
•
•
•
•
Cooktops
Microwave ovens
Built-in ovens
Range hoods
Permits for the work are described and enumerated.
Testing and hot checking the entire system is measured as an item.
Fire stops and flashings are described and enumerated.
Cutting, drilling, and patching required for this work are described and
enumerated.
Cleanup resulting from this work is measured as an item.
Estimating Shortcuts
• Instead of a full takeoff on many plumbing,
HVAC, and electrical, estimators use shortcuts
to compute their prices for the work.
• With plumbing, HVAC, and electrical trades, a
price per square foot of gross floor area could be
used to provide a rough estimate of the cost, but
more accuracy may sometimes be required.
Quick Estimates of Plumbing Work
• A quite accurate estimate for plumbing work can be
obtained quickly by means of a unit price for each
plumbing fixture.
• Enumerating fixtures and multiplying by the
applicable price for each fixture can give an
accurate price for the complete plumbing work.
• Additional prices may be required for installing
appliances, special fixtures, and any out-of-theordinary plumbing work.
Plumbing Example
• Estimate the price of a three-fixture bathroom based
on the following prices for the fittings involved:
–
–
–
–
–
–
1 bathtub 72” x 36”
1 water closet
1 lavatory basin 19” x 16”
-
Extra for pipe and fittings 30%
Total
$2,425
$1,450
$845
$4,720
$1,416
$6,136
Quick Estimates of HVAC Work
• HVAC work can be estimated quite quickly by using
a combination of prices per unit area and unit prices
for items of equipment.
• To estimate the total cost of ductwork, multiply the
unit price from a past project by the gross floor area
of the new house.
• To complete an HVAC estimate, determine how
many items of equipment are required, and multiply
by the appropriate item price for each item.
HVAC Example
• Estimate the price of a 2,200-square feet
house with a special humidifier and exhaust
fan:
– Basic HVAC 2,200 SF at $4.25/ SF
– Humidifier
– Exhaust Fan
–
Total:
$9,350
$2,000
$250
$11,600
Quick Estimates of Electrical Work
• Electrical work can also be estimated quickly by means of a
combination of prices per unit area and prices for items of
equipment and fixtures.
• For power wiring and fittings, multiply the number of power
outlets by inclusive price per outlet.
• For equipment and fixtures, multiply number of each item by unit
price for that item, including:
– Electrical panels
– Sub-panels
– Light fixtures
– Etc.
Electrical Example
• Calculate the electrical price for a 2,200square feet house including a security system
with motion detectors:
– Basic electrical:
2,200 SF at $6.75/ SF
– Add security system
–
Total:
$14,850
$2,500
$17,350