From boilers and furnaces, to pipe, ductwork, and fittings, Capitol District Supply is your best bet for heating and air-conditioning equipment and supplies. We’re proud to be a major representative for IBC , ‘Better Boilers’, as well as stocking everything for most HVAC Systems, and are known as Radiant Heating Specialists!

Heating & Air Conditioning

Boilers: Smith, Embassy, Triangle Tube, Slant-Fin, Navien, IBC
Furnaces: Goodman, Olsen Gas, Oil , Miller, Century
Air Conditioning: Goodman, Century
Radiant Infloor: Viega, Zurn
Space Heaters: Empire Direct & Chimney Vent
Unit Heaters: Oil, Gas, Water & Steam, Beacon Morris
Baseboard: Embassy
Controls: Honeywell, White Rogers, Watts, Argo, Tekmar, Hydrolevel
Circulators: Taco & Grundfos
Power Venters: Field
Zone Dampers: Arzel
Zone Valves: Automag, Honeywell, Taco
Heating Accessories: Hercules Anti-Freeze, GeneralAire, Lux Thermostats, Ultra-Fin, Vent-Rite, DiversiTech, TracPipe & Counter Strike Flexiable Gas Tubing: 1/2″-1″
ConStab Underground Poly Gas Pipe: 3/4”-2“
Acetylene Refills – Saratoga Only

Water Heaters

American: Natural Gas, Electric, Propane
John Wood: Oil
Navien: Tankless, Combi System
IBC: Indirect, Multi Energy Tanks, Combi System
Vaughn: Indirect boiler fired, WH 35-70 gal.


Round Pipe & Fitting: 3” – 24” insulated flex 5”-18”
Trunk Duct Fittings: 8” x 8” to 8” x 30”
Boots, Takeoffs: etc 5” – 10”
Oval Pipe & Fittings: 6”, 7” & 8″
Plenums, Wall Stack, Panning, Rain Caps, Dampers, Ameri-Vent Registers: floor, wall, ceiling, T-Bar, J&J Register

Chimney Pipe (Gas/Oil/Wood)
Air Jet: Gas 4” – 10”, oil/wood 6” & 8”,
Aluminum Chimney Flexliners
Protech Stainless Steel Venting systems

we do



  • Heating and cooling load calculations
  • radiant loop diagrams using Wrightsoft software systems
  • Visio & Tekmar piping and wiring diagrams


What We Can Do For You

At Capitol District Supply, we work with contractors and homeowners to find the best fit for a property’s heating and air conditioning needs. We always recommend that a qualified contractor install a heating or air conditioning system.

If you want to update and improve your heating or air conditioning system, we recommend letting us calculate a Heat Gain Load (Heat Loss) to determine the best unit for your home. This calculation will take into consideration the size of your home, the number and size of doors and windows (where air escapes), and which direction your house faces (to address how the sun affects the temperature in your home).

5%A Heat Gain Load is done for both new construction and existing homes. In order to complete the calculation for your property, we need:

  1. Sketch of the floor plan for the house (width, length, height dimensions)
  2. Window and exterior door dimensions, type, location, and direction (North, South, etc)
  3. R-Value of insulation in walls, ceilings, floors

Once we complete a Heat Gain Load, we will know the BTUs lost from the home and can match the net output of the furnace or boiler to best fit your home. This will allow you to purchase a unit that will be the best investment for performance and energy usage