Renovating an older home is one of the most rewarding projects a homeowner can take on. Whether you’re updating a century-old farmhouse, restoring a mid-century ranch, or modernizing a home that’s simply been around the block a few times, the transformation can be remarkable. But older homes come with a unique set of challenges — and your heating and cooling system is one of the most important things to evaluate before, during, and after a renovation.
At John’s Heating & A/C, we work with Southwest Iowa homeowners renovating older homes every season. HVAC is often an afterthought in the excitement of a remodel — until something goes wrong, costs spike, or a brand-new renovation is undermined by a system that can’t keep up. This guide covers what you need to know about heating and cooling when renovating an older home, so you can plan ahead, budget wisely, and end up with a home that’s as comfortable as it is beautiful.
This article draws on educational insights from our equipment partner, American Standard® Heating & Air Conditioning. You can read their original article here: Renovating an Older Home
Why HVAC Is One of the First Things to Evaluate When Renovating an Older Home
It’s tempting to start a renovation with the fun stuff — new flooring, updated kitchens, fresh paint. But if you’re renovating an older home, your HVAC system deserves an early and honest assessment for a few important reasons.
Old systems may not survive a renovation. Dust, debris, and disruption from renovation work can put significant stress on aging HVAC equipment. A system that was limping along before demo begins may not make it through — and discovering that mid-renovation is far more disruptive and expensive than planning for it upfront.
Renovation changes your home’s heating and cooling needs. Opening up floor plans, adding square footage, improving insulation, or replacing windows all change how heat moves through your home. A system that was barely adequate before a renovation may be completely wrong for the home after it.
HVAC installation is far easier during a renovation. Running new ductwork, installing equipment, or making electrical upgrades is significantly less invasive — and less expensive — when walls are already open. Waiting until after a renovation is complete means tearing into freshly finished spaces.
Starting your HVAC evaluation early gives you more options, better pricing, and a smoother project overall.
Common HVAC Challenges in Older Homes
When renovating an older home, you’re likely to encounter some combination of these heating and cooling challenges. Understanding them upfront helps you make smarter decisions about what to fix, upgrade, or replace.
Aging or Inefficient Furnaces
Older gas furnaces are a common pain point when renovating an older home. Furnaces installed 20 or more years ago are typically far less efficient than modern models — often operating at 60–70% efficiency compared to today’s high-efficiency units, which can reach 96–98% efficiency or higher.
A few things to watch for when evaluating an older furnace:
- Age. If the furnace is over 20 years old, replacement is worth serious consideration — especially if you’re already investing in a major renovation.
- Pilot light. Most furnaces manufactured in the last 15–20 years use electronic ignition rather than a standing pilot light. If your furnace still has a pilot light, it’s almost certainly an older, less efficient model.
- Rising gas bills. If your heating costs have been climbing without a clear explanation, a degrading furnace may be the culprit. As furnaces age, they lose efficiency and burn more fuel to produce the same amount of heat.
- Frequent repairs. If the furnace has needed multiple repairs in recent years, continuing to invest in it may cost more than replacing it — especially alongside a renovation when installation is more accessible.
Upgrading to a high-efficiency furnace during a renovation is one of the smartest investments you can make. The energy savings compound over time, and you’ll be starting the next chapter of your home’s life with reliable, efficient heat.
Ductwork: Outdated, Undersized, or Nonexistent
Ductwork is one of the biggest HVAC wildcards when renovating an older home. Depending on the age and history of your home, you may be dealing with:
- Outdated duct materials. Some older homes have ductwork made from materials that have degraded over time, including flex duct that has collapsed or disconnected, or even older materials that are no longer considered acceptable for modern systems.
- Undersized ducts. Ductwork installed decades ago may have been sized for the equipment of that era. When paired with a modern, higher-capacity system, undersized ducts restrict airflow and undermine system performance.
- Leaky duct connections. Over time, duct joints and connections loosen and develop gaps. The average home loses 20–30% of conditioned air through duct leakage — air that never reaches your living spaces.
- No ductwork at all. Many older homes — particularly those built before central HVAC was standard — have no existing duct system whatsoever.
If your home has functional, well-sealed ductwork in good condition, you may be able to work with it. If not, renovating an older home is the ideal time to address ductwork issues before walls are closed back up.
Ductless Mini-Split Systems: A Smart Option for Older Homes
For older homes without existing ductwork — or homes where adding full ductwork would be prohibitively expensive or disruptive — a ductless mini-split system is often the most practical and efficient solution.
A ductless mini-split consists of two components: an outdoor condenser unit and one or more indoor air handlers mounted on walls or ceilings throughout the home. Refrigerant lines connect the two through a small opening in the wall — no ductwork required.
The advantages of ductless systems for older homes are significant:
- No ductwork needed. This eliminates the single biggest installation expense and disruption in homes without existing ducts.
- Zone control. Each indoor air handler operates independently, allowing you to heat and cool different areas of the home to different temperatures — a major comfort upgrade over single-zone systems.
- High efficiency. Ductless systems are significantly more efficient than window units and comparable to or better than many traditional ducted systems.
- Flexible installation. Indoor units can be mounted in locations that work for your home’s layout without major structural changes.
- Heating and cooling in one. Most ductless mini-splits function as heat pumps, providing both heating and cooling from a single system — eliminating the need for a separate furnace in some applications.
For Southwest Iowa homeowners renovating an older home without existing ductwork, a ductless mini-split system is well worth discussing with John’s Heating & A/C.
Electrical Capacity
This is one of the most overlooked considerations when renovating an older home — and one of the most important. Older homes frequently have electrical systems that were designed for a fraction of the power demand of a modern household. Standard 60-amp or even 100-amp panels were common in homes built before the 1970s, and many of these panels simply can’t support modern HVAC equipment without upgrades.
Even ductless mini-split systems — which are more efficient than many alternatives — require a dedicated circuit and adequate electrical capacity to operate safely and effectively. Before planning any HVAC installation as part of your renovation, have a licensed electrician assess your home’s electrical system and identify any upgrades that may be needed.
Catching electrical limitations early prevents costly surprises mid-project and ensures your new HVAC equipment operates safely from day one.
Insulation and Air Sealing
HVAC equipment can only do so much if the home itself is leaking conditioned air. Older homes are frequently under-insulated by modern standards, and decades of settling, shifting, and aging can open gaps around windows, doors, electrical outlets, and penetrations throughout the home.
When renovating an older home, improving insulation and air sealing alongside your HVAC upgrade is one of the highest-return investments you can make. A well-insulated, well-sealed home requires less heating and cooling capacity to stay comfortable — which means smaller equipment, lower energy bills, and less wear on your system over time.
Common areas to address when renovating an older home include:
- Attic insulation — the single most impactful area in most older homes
- Crawlspace or basement insulation and vapor barriers
- Air sealing around windows, doors, and electrical penetrations
- Insulating and sealing ductwork in unconditioned spaces
John’s Heating & A/C can help you understand how your home’s insulation and air sealing affect your HVAC needs and right-size your equipment accordingly.
Planning Your HVAC Upgrade During a Renovation
If you’ve determined that your older home needs HVAC upgrades as part of your renovation, here’s how to approach the process.
Get an HVAC assessment before finalizing your renovation budget. Understanding what your system needs — and what it will cost — early in the planning process prevents budget surprises and allows you to make smarter decisions about the overall project scope.
Coordinate HVAC work with other trades. HVAC installation involves mechanical, electrical, and sometimes structural work. Coordinating your HVAC contractor with your electrician, plumber, and general contractor from the start reduces conflicts and keeps the project on schedule.
Don’t size equipment based on your old system. Old equipment was often improperly sized to begin with — and renovation changes your home’s heating and cooling load. A proper Manual J load calculation from John’s Heating & A/C ensures your new system is sized correctly for the home you’re creating, not the home as it was.
Think long term. A renovation is a long-term investment in your home. HVAC equipment installed during a renovation should be chosen with efficiency, reliability, and longevity in mind — not just the lowest upfront cost.
Trust John’s Heating & A/C for Your Renovation HVAC Needs
Renovating an older home is a big undertaking, and getting the HVAC right is one of the most important decisions you’ll make along the way. At John’s Heating & A/C, we help Southwest Iowa homeowners navigate heating and cooling decisions during renovations of all sizes — from single-room updates to whole-home overhauls.
As a trusted American Standard® partner, we have access to high-efficiency heating and cooling equipment designed to perform reliably for years to come. Whether you’re evaluating an aging furnace, exploring ductless options, or planning a full HVAC replacement alongside your renovation, our experienced team can help you find the right solution for your home and your budget.
Call John’s Heating & A/C today to schedule a service call. Let’s make sure your renovation ends with a home that’s as comfortable and efficient as it is beautiful.
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Portions of this article are adapted from educational content published by American Standard® Heating & Air Conditioning: “Renovating an Older Home” September 6, 2022.