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 pairing your furnace with a cold-climate heat pump for dual-fuel efficiency, Design Heating delivers properly sized, professionally installed forced-air systems across the Duluth, MN area. For homes without ductwork, our ductless cold-climate mini-splits are usually the better fit.
Quick Answer
What does furnaces & ac cost in Duluth, MN?
In the Duluth, MN area, a high-efficiency 96% AFUE gas furnace replacement typically costs $5,500 to $9,500. Adding central air conditioning to an existing furnace is usually $4,500 to $8,000. We size systems with a Manual J load calculation — never by rule-of-thumb — and for homes that want heat-pump efficiency with gas backup we design dual-fuel systems rated for Duluth winters down to -15°F or lower.
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 also add central air conditioning for summer cooling, or pair a cold-climate heat pump with your furnace for an efficient dual-fuel system. (For homes without ductwork, our ductless mini-split heat pumps are usually the better fit.)
- High-efficiency furnace replacements
- Central A/C addition to existing ductwork
- Dual-fuel furnace + heat pump systems
- Variable-speed, two-stage equipment options
Why Choose This System
Engineered Benefits, Not Sales Pitches
Dual-fuel ready
Pair a high-efficiency furnace with a cold-climate heat pump and the system runs on the heat pump in mild weather, switching to gas on the coldest days — the most efficient forced-air option for our climate.
Right-sized ductwork
We run a Manual D duct review so your existing ductwork can actually deliver the airflow the new equipment needs — the step most replacements skip.
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.
-
1. Manual J load calc
We size the furnace or AC to your home — never by replacement rule-of-thumb.
-
2. Manual D duct review
For forced-air installs, we check that your existing ductwork can deliver the airflow the new equipment needs.
-
3. Install + permits
We pull permits, replace the equipment, and route condensate, gas, and electrical to code.
-
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
Sized by calculation, not guesswork
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.
For new furnace installations in Minnesota, look for 95% AFUE or higher. We typically install 95–98% AFUE condensing gas and propane furnaces from tier-1 manufacturers such as AirQuest and Goodman, sized to your home with a Manual J calculation.
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 whenever the right size isn't a straightforward like-for-like match.
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.
Have a question we did not cover?
Ask Kevin directly
Ready to Get Started?
Free in-home consultation, Manual J heat-loss calculation, and a written, itemized quote — every time.