Replacing Twin Furnaces With Variable Speed and Ductless in Audubon, NJ

Uneven heating and cooling is a common problem for homes two stories (or more) with forced heat. Thanks to thermostat placement and air leakage, the upstairs rooms don’t get treated as well as the first floor. 

For years, our homeowner in Audubon, NJ, had a two-furnace system addressing the problems. But, even that had its drawbacks.

That’s why she combined a variable-speed furnace with a ductless mini split. 

In this case study, we’ll talk about the challenges our homeowner faced. Then, we’ll see the benefits and drawbacks of the two-furnace system. 

Finally, we’ll look at how her new setup addresses all of it.

Problem: A homeowner wanted to replace twinned gas furnaces in her colonial home in Audubon, NJ. Even with two furnaces, the house was never quite warm enough. And they produced very high heating bills and maintenance costs. 

Solutions: Installed a variable-speed gas furnace with air conditioning and a Mitsubishi ductless mini split for two rooms with no ductwork. 

Heating Challenges with Forced-Air Ductwork

As we mentioned, thermostat placement and air leakage contribute to uneven heating and cooling. But there’s a little more to it than that — especially for this home in Audubon, NJ. 

Thermostats and Ducts

With one thermostat, the second floor is often warmer or cooler than the first. That’s because the system only measures in the room with the gauge. 

The second problem is air leakage. The ductwork isn’t perfectly sealed. So, some of the treated air gets lost along the way. 

There’s also a loss in pressure over each floor the air has to travel. By the time it reaches the bedrooms, it’s not nearly as powerful.

Attics and Dormers

The next challenge our homeowner faced was the attic rooms. This home had a raised dormer. This makes it so the attic has a high enough ceiling for people to use it as a room. 

In this case, our homeowner had the attic split into two rooms. It added a lot of space but made heating and cooling a challenge. 

What happens is that heat rises. And it collects in the attic. 

That means, in the summer, it gets trapped there. The outside is hot, so the heat stays up there. And it affects the floor below it. 

Then, in the winter, the warmth rises to the attic and then keeps going. It escapes through any unsealed space up there. 

Because of all this, our homeowner went for a twin furnace system years ago. And, back then, it was probably the best bet. 

But, it still wasn’t a perfect system. And, today, there are better options out there. So, as those heaters got older, our homeowner started looking for better ways to heat and cool her home. 

Pros and Cons of a Two-Furnace Home

Three benefits of a two-furnace home are: 

1. More customizable settings

2. Better heating and cooling upstairs

3. Less Wear and Tear

Three drawbacks are: 

1. Less Room in the House

2. More Repair and Maintenance Expenses

3. The Attic was Still Untreated

Pros of a Twin System

Our homeowner originally opted for the twin system because it would finally get the upstairs the treatment it needed. 

There’s another thermostat upstairs connected to the second furnace. So, one heater handled that area individually. 

And, with two machines for the house, neither one worked as hard as one would when handling the same space. That added to the lifespan of each one. 

But, over time, our homeowner noticed some shortcomings. 

Cons of a Twin System

First of all, having two furnaces meant twice the maintenance costs. And upkeep is even more important with a setup like this. 

If you’re twinning furnaces, they have to be identical units. If one goes, the whole system is shot. 

Next, there was less space in the house with two large furnaces in it. And two motors and blowers meant more noise. 

Finally, the two attic rooms didn’t have ductwork. So, neither of the units covered the third floor. 

So, as the units got older, our homeowner looked for better options.

Variable-Stage Furnaces and Ductless Mini Splits

When our homeowner called ECI, she had a few ideas in mind. And, once we saw the house, we helped her decide on a combination of solutions. 

Variable-Stage Furnace

With a variable-stage furnace, our homeowner would get the heating and cooling she’d need throughout the house. And, she’d get just the right amount for any weather. 

The difference between these and traditional furnaces is that variable speed furnaces do much more than just turn on and off. 

Instead, they use as much or as little power as necessary, given the temperature. As a result, the system remains in a low-power mode much of the time. 

They don’t cycle on and off a few times every hour when the temperature drops. Instead, one furnace will heat or cool the entire home, then run quietly and efficiently to maintain the temperature. 

Well, in this case, it treats almost the entire home. 

Ductless Mini Split

Rather than install more ductwork, our homeowner went with a mini split for the attic rooms. This system is efficient and effective. It’ll keep those rooms the exact temperature she wants — making it a lot easier to keep the second floor comfortable. 

You can read more about how this works in our learning library -  here and here .

Up in the attic, we installed two air handlers — one in each room. They both have thermostats on them. So, our homeowner can set each one separately. 

From there, we run a line set down to an outdoor heat pump. 

Inverter technology

This system also uses variable speed. Here, it’s usually referred to as inverter technology. 

So, once again, it’s rarely working at full capacity. It’s also whisper-quiet: At their loudest, the air handlers produce about as much noise as leaves rustling. 

Finally, after all these years, our homeowner has complete control over the heating and cooling throughout the house. 

Each room feels more comfortable than it ever has before. And, thanks to the energy-efficient variable-stage systems, her energy bills have never been lower. 

If you’ve never had the home comfort you wanted, call ECI. We’ve worked on just about any type of home, with any kind of setup, you can imagine. With a free consultation, we’ll help you find the heating and cooling system that’s perfect for you.