95%+ AFUE furnaces
We install high-efficiency condensing gas and propane furnaces that turn 95–98 cents of every fuel dollar into heat.
Service 05
Furnaces & Air Conditioning
Whether you are replacing an aging furnace, adding central air conditioning, or installing ductless mini-splits to cool a home without ductwork, Design Heating delivers properly sized, professionally installed forced-air and cold-climate heat pump systems across the Duluth, MN area.
Overview
Custom-Designed for Duluth Homes
A high-efficiency furnace upgrade is one of the fastest ways to cut energy costs and increase comfort. If your home has forced-air ductwork, we can add central air conditioning for summer cooling. No ductwork? We install ductless mini-split heat pumps that provide cooling and supplemental heat without tearing into walls.
- High-efficiency furnace replacements
- Central A/C addition to existing ductwork
- Ductless mini-split heat pump installation
- Heating and cooling in one unit (mini-splits)
Why Choose This System
Engineered Benefits, Not Sales Pitches
Mini-splits work down to -15°F
Modern cold-climate ductless heat pumps from Mitsubishi and Fujitsu deliver heat reliably at Duluth winter temperatures.
No ductwork? No problem
Ductless mini-splits provide heating and cooling in any room without tearing into walls or running ducts.
Quiet, two-stage operation
Variable-speed equipment runs longer at lower speeds — quieter, more even temperatures, lower humidity in summer.
Our Process
How a Furnaces & AC Project Works
Every job follows the same documented workflow — from heat-loss calculation to final commissioning.
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1. Manual J load calc
We size the furnace, AC, or mini-split to your home — never by replacement rule-of-thumb.
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2. Manual D duct review
For forced-air installs, we check that your existing ductwork can deliver the airflow the new equipment needs.
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3. Install + permits
We pull permits, replace the equipment, and route condensate, gas, and electrical to code.
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4. Startup & test
We measure static pressure, refrigerant subcool, and gas-input — and document it for the manufacturer warranty.
Credentials
Owner-Installed, Owner-Accountable
Kevin Kaski personally designs and installs every Design Heating project — no sub-contractors, no rotating crews.
License
MN MB715020
Minnesota Licensed & Bonded
Geothermal
CGD Certified
IGSHPA Accredited Trainer & Installer
Engineering
Manual J + LoopCad
Every system sized by calculation, not guess
Reputation
4.9 ★ · 114 reviews
BBB Accredited · Founded 2016
Service Area
Where We Install Furnaces & AC
Design Heating is based in Duluth, Minnesota and serves homeowners throughout Northeastern Minnesota and Northwestern Wisconsin — typically within a 30-mile radius of our shop on Washburn Road.
Design Heating, LLC5131 Washburn Road
Duluth, MN 55803
(218) 525-5914
- Duluth, MN
- Hermantown, MN
- Proctor, MN
- Pike Lake, MN
- Cloquet, MN
- Esko, MN
- Carlton, MN
- Two Harbors, MN
- Superior, WI
Frequently Asked Questions
Furnaces & AC — Common Questions
A high-efficiency (95% AFUE+) natural gas or propane furnace installation in the Duluth area typically runs $5,500–$9,500, including permit, removal of the old unit, and startup. We provide written, itemized quotes after a free in-home visit.
Adding a central air conditioner to an existing forced-air system in the Duluth area typically runs $5,000–$8,500 installed, depending on tonnage and refrigerant line routing. Existing ductwork must be sized appropriately — we verify with a Manual D review.
Yes — modern cold-climate mini-splits (look for the NEEP Cold Climate Air Source Heat Pump listing) deliver rated capacity down to about 5°F and continue producing heat at -15°F. For Duluth homes, we recommend cold-climate units as primary heat with a backup heat source for the coldest 1–2% of hours.
Furnace sizing is determined by an ACCA Manual J heat-loss calculation — not by the size of the unit being replaced. Over-sized furnaces short-cycle, reduce comfort, and shorten equipment life. We run Manual J on every replacement project.
A like-for-like furnace replacement is usually completed in a single day. Adding A/C or upgrading ductwork adds 1–2 additional days.
For most Duluth-area homes with existing natural gas, a furnace with a cold-climate heat pump (a "dual fuel" system) offers the best of both — heat pump operation during mild weather for efficiency, gas backup on the coldest days. We will model both options during design.
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Ready to Get Started?
Free in-home consultation, Manual J heat-loss calculation, and a written, itemized quote — every time.