Winchester 80% Efficiency Single Stage Multi-Position Gas Furnaces


The 80% AFUE W8M Series furnace is a great choice when replacing old inefficient residential furnaces for apartments, rental properties, or commercial applications.  It can be installed in upflow or horizontal applications and can be easily converted for downflow applications.The compact cabinet height of only 33″ makes the unit perfect for basements, closets, attics, garages and commercial applications. The furnace is air conditioning ready with an adjustable speed blower motor for maximum comfort. All units are factory assembled, wired and tested to assure safe, dependable and economical operation. Not approved for mobile home installation. Not approved for installation in CA per new emissions standards.

10-Year Limited Parts Warranty*
20-Year Heat Exchanger Warranty

WARNING: Cancer and Reproductive Harm –

*Please Note: To qualify for the extended 10-Year Limited Parts Warranty, the unit must be registered online at within 90 days of purchase for replacement or closing for new home construction. Otherwise, the standard 5-Year Limited Parts Warranty is in effect.

Tech Guide

User Guide

Installation Manual


Natural gas ready, may be field converted to LP Gas (Propane) with optional conversion kit (LP 347)

Multi-positional compact cabinet height of 33 inches

Minimal conversion for downflow application (additional clearance needed for venting)

Control board with high level self-diagnostics and fault code displays to save time on servicing and troubleshooting

Electronic hot surface ignition increases safety and efficiency

Direct Drive, permanently lubricated blower motor has adjustable speed to maximize comfort level

Induced combustion system with in-shot main burners for quiet, efficient operation

4″ Flue Connection

High tech tubular aluminized steel primary heat exchanger

Not Certified for Mobile Home use

Not Certified for use in California

Sizing Guide


You can refer to an estimate or proposal from a local contractor, refer to the size of your existing system that you may want replaced, or use the sizing estimation chart provided on this page. Use the map to determine your Region based on the location of your home. Using the equipment charts, find your Region and go down the column to locate the range that covers the Square Footage of your home. Follow the row to the right to determine the recommended Furnace for your application.



Square Footage of Your Home Furnace Model
624-780 675-840 750-940 915-1140 1025-1280 W8M040-214
780-1170 840-1260 940-1410 1140-1710 1280-1925 W8M060-314
1170-1560 1260-1680 1410-1880 1710-2280 1925-2550 W8M080-317
1560-1950 1680-2100 1880-2350 2280-2850 2550-3200 W8M100-317
1950-2340 2100-2525 2350-2825 2850-3425 3200-3850 W8M120-521


NOTE: These tables an charts are intended to be used as a guideline only. The information is based on conventional window space (<15%), insulation and building construction. Only use these tables as a reference. When including a finished basement, use 1/2 of the finished basement square footage with the rest of the area being calculated.

Models & Specs

80% AFUE Multi-Positional Gas Furnace Models

Hamilton Model Number BTU Input/Output Dimensions H x W x D (in.) Available Tons Outlet Opening Weight (lbs.) Energy Guide
W8M040-214 40,000 / 32,000 33 x 14.5 x 29.5 1.5 – 2.0 13.375 x 20 103 EnergyGuideIcon2
W8M060-314 60,000 / 48,000 33 x 14.5 x 29.5 1.5 – 3.0 13.375 x 20 108 EnergyGuideIcon2
W8M080-317 80,000 / 64,000 33 x 17.5 x 29.5 2.0 – 3.0 16.375 x 20 118 EnergyGuideIcon2
W8M100-317 100,000 / 80,000 33 x 17.5 x 29.5 2.0 – 3.0 16.375 x 20 123 EnergyGuideIcon2
W8M120-521 120,000 / 96,000 33 x 21 x 29.5 3.5 – 5.0* 19.875 x 20 145 EnergyGuideIcon2

*Please Note: 5 Ton/2000 CFM applications require two (2) side air returns.

Optional Furnace Accessories

Item No. Description Weight (lbs.)
LP 347 LP (Propane) Conversion Kit for all Gas Furnaces 1
RA 16 Return Air Drop Assembly (Upflow Applications Only) 50
WKDP 20 Universal Trim to Fit Plenum – 20″ x 20″ x 47″ (for Heat Only Applications) 28
CB 414/514 Combustible Base for 14.5″ Downflow Applications – Heat Only* 8
CB 417/517 Combustible Base for 17.5″ Downflow Applications – Heat Only* 9
CB 421/521 Combustible Base for 21″ Downflow Applications – Heat Only* 10
CB 524 Combustible Base for 24.5″ Downflow Applications – Heat Only* 11

*Please Note: Combustible Base is only required for downflow, heat only applications where the surface is combustible (ex. wood sub-floor).

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