In Southwest Portland, mid-century modern architecture is abundant. The architectural style’s flat roofs, exposed beams, and masonry fireplaces are a beautiful part of the local cityscape. However, they can also lead to a few complications when getting a furnace replacement.
Modern furnaces have grown incredibly energy efficient, reducing the amount local residents have to pay for energy bills. While many local homeowners want to replace older furnaces with more efficient models, this process typically requires high-efficiency furnace venting.
This added cost is often surprising to homeowners who have existing venting in their home. Unfortunately, the cost is unavoidable if you’re upgrading your furnace. Today’s units work in fundamentally different ways than units did back in the 1950s. Trying to reuse the old infrastructure is not just inefficient. It can also be dangerous for the safety of your family and home.
To learn more about getting a high-efficiency furnace installation in Southwest Portland, read on.
The Science: Hot Exhaust vs. Cool Condensate
Years ago, typical furnaces were able to achieve an 80% energy efficiency. This means that 20% of their heat went up the chimney, resulting in lost heat and high energy bills.
However, this type of heat loss was actually a necessity to vent the home. The wasted heat warmed the masonry, which allowed the exhaust gases to be buoyant enough to rise out of the chimney.
Today, furnaces can achieve a remarkable 96% energy efficiency. They are able to extract almost all of the heat by cooling the exhaust through a primary exchanger, a secondary exchanger, and a fan. The water vapor in the cooled air becomes a liquid, which must be drained through the PVC furnace exhaust piping. Then, a fan is used to push the remaining gas out of your home.
If the cool, wet exhaust is sent into a traditional masonry chimney instead of a PVC pipe, it won’t drift away. Instead, it will trickle back down as acidic water and lead to moisture damage.
Why You Cannot Use the Old Chimney
When you get a mid-century modern heating upgrade, you can’t use the old chimney. Because of how a 96% efficient furnace installation works, there is a risk of ice damming, structural damage, and acidic condensate.
- Acidic Condensate: Natural gas combustion produces water that is naturally liquid. If this acidic condensate enters your chimney, it can eat through the bricks, mortar, and clay liners.
- Structural Damage: Even if you aren’t concerned about the acidic nature of the liquid, the presence of water vapor can cause significant damage. As it sinks into the chimney breast, it can destroy your home’s drywall and plaster.
- Ice Damming: During Portland’s winters, freezing temperatures can cause moisture to turn to ice. Over time, this can cause cracks to develop in the chimney’s structure.
The Solution: PVC “Two-Pipe” Venting
When getting a high-efficiency furnace installation in Southwest Portland, the best option is to use two-pipe venting instead of a chimney. Two PVC pipes make up a sealed combustion system. While one PVC pipe is responsible for pulling fresh air in from the outdoors, the other pushes exhaust out.
To install this system, you can try venting the gas furnace out a side wall or the roof. Mid-century modern homes often have flat or low-pitch roofs, making sidewall venting the more popular and discreet option. No matter which option you choose, we can paint and route the pipes so that they are in keeping with the architectural beauty of your home.
The “Orphaned” Water Heater Issue
When we evaluate your home for a furnace replacement, we also have to consider whether orphaned water heater venting will be a problem. In many older homes, furnaces and water heaters share the same chimney. When a new furnace replacement is set up with a different venting method, the water heater is “orphaned” and left alone.
This is an issue because the old furnace was largely responsible for keeping the chimney warm. Without this warmth, the exhaust gases won’t be buoyant enough to exit the home. If only the water heater uses the chimney, there won’t be enough of a draft to push the fumes out. As a result, backdrafting can cause carbon monoxide to enter your home.
For orphaned water heaters, we recommend choosing one of two options. A chimney liner can be installed for the water heater. Alternatively, a new tankless unit can be installed that vents via a PVC pipe.
Why Trust Central Air Heating, Cooling & Plumbing With Your Vintage Home
Over the years, our team has developed a reputation for our skilled retrofits, exceptional code compliance, and knowledgeable staff members. When residents need a furnace installation in Southwest Portland, they turn to us for a few key reasons.
- Retrofit Specialists: Mid-century moderns pose unusual architectural challenges. Thanks to our unique framing and crawlspace abilities, we can maintain the aesthetic appeal of Portland’s post-war housing stock while ensuring your furnace is optimally installed.
- Code Compliance: Our experienced HVAC technicians understand local permitting rules, so we can ensure your installation meets and exceeds Oregon’s mechanical codes. From proper clearance to termination points, we’ll make sure your HVAC system is up to code.
- Design Sensitivity: When installing high-efficiency furnace venting, we do our best to make it as invisible as possible.
Frequently Asked Questions: Furnace Venting Upgrades
Can’t you just put a liner in the chimney for the furnace?
While it is technically possible to install a furnace chimney liner in Portland, this is often a cost-prohibitive measure. Additionally, it is less efficient than using PVC venting for furnaces that have a 90% efficiency or higher.
Will the new pipes be ugly on the side of my house?
We have years of experience installing high-efficiency furnace venting. Our team can install low-profile termination kits that blend in with your walls and siding. After the kit is installed, we can also paint the PVC so that it matches your siding completely.
Why is my bid higher than my neighbor’s, who kept their chimney?
If your neighbor kept their chimney, then they likely installed a lower efficiency (80%) unit. In addition to being difficult to find anymore, these units are more expensive in the long run.
