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-the- ordinary 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”-$2,425 –1 water closet-$1,450 –1 lavatory basin 19” x 16”- $845 –$4,720 –Extra for pipe and fittings 30%$1,416 –Total$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$9,350 –Humidifier$2,000 –Exhaust Fan$250 – Total: $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 2,200- square feet house including a security system with motion detectors: –Basic electrical: 2,200 SF at $6.75/ SF$14,850 –Add security system $2,500 – Total:$17,350