Husband and wife start-up entrepreneurs Pierre Delforge and Jane Melia dealt with the untimely demise of their home's gas furnace just like any average adult couple would.

Well, maybe not just like any average adult couple.

Unless that couple happens to be made up of two Ph.D. Cambridge University engineers – engineers who, by vocation, avocation, livelihood, and personal passion, tend to address day-to-day household operational challenges as more than an occasion to hire a residential replacement contractor and have that be the end of it.

Far more. In fact,

For Delforge and Melia, co-founders and principals of award-winning construction technology and smart home energy platform Harvest Thermal, a San Francisco Bay Area start-up, their domestic room air comfort pain may work out to be countless others' gain.

Harvest’s groundbreaking Smart Thermal Battery™.

We did use our own home as a guinea pig and a test ground," Delforge tells us on the heels of Harvest's recognition by PCBC and the Gold Nugget Awards as the winner of the Grand Prize for Innovative Housing Concepts - Construction Technology for Next Generation HVAC for its project at a KB Home development in Manteca, CA. "We were so surprised and thrilled about the improvement. With a furnace, typically, it's on and off, you get a blast of hot air for five minutes, and then it's off for 10 minutes, and it starts again. We tend to get used to it. But it's nowhere near as comfortable as the experience of having variable, modulated heat and delivering constant temperature quietly and seamlessly. That's the experience that we provide with the Harvest system."

What started with a home furnace problem in 2018 turned into this:

[Harvest combines] heat pump technology with thermal energy storage to uniquely slash home emissions, reduce monthly heating bills, and offer residents superior comfort. For home builders, it captures higher incentives and tax credits."

Apart from collecting the Gold Nugget recognition, Delforge took time last week to help homebuilding operators and their partners better understand what Harvest Thermal is, what builders need to know, and why it matters. Pierre joined KB Home's Jacob Atalla, VP for Sustainability Initiatives, at PCBC's two-day Innovation Hub mini-presentations, explaining the game-changing big picture potential of the Harvest solution and where it fits into an exceptionally innovative homebuilder's ongoing explorations of how to lead the way in developing new ways to add value to its homebuyer and residents' ownership experience.

Atalla, who for years has spearheaded and championed epic-level strategic and operational partnerships with manufacturers, systems solutions, power suppliers, and other members of the KB Home vendor ecosystems, recognized Harvest and its breakthrough Smart Thermal Battery as an especially attractive home innovation opportunity, both for its impact on a home's cost-to-own, its room air comfort, and its potential as an off-grid source of resilient energy supply to the house. He said KB Home tilts favorably to a solution in the HVAC system that requires no added complexity, architectural changes, or significant first-cost increase that homebuyers would have to bear.

With new and emerging Federal and state energy credits that homebuilders and residents can tap into, the system nets out to an expense win on both fronts.

Per a press statement:

The Harvest system will reduce building energy code compliance costs, make meeting Energy Star and Zero Energy Ready standards easier and cheaper, and earn higher bonus rebates from the California Energy Smart Homes program. It shifted 84% of the energy used for heating and hot water to off-peak times enabling low-carbon, low-cost operation.

The Harvest Pod® operates a heat pump to store heat when solar electricity is cheap, clean, and plentiful. The stored heat is distributed from the heat battery as space heat and hot water whenever needed – especially in mornings and evenings when people rely on their heating and hot water, and the grid is dirtier and more expensive. The system cuts emissions by 90% compared to gas, 40% lower than an equivalent heat pump system. And it lowers monthly heating and hot water bills by up to 30%."

The fact is, what makes the Harvest system appealing to homebuilders like KB, not to mention custom homebuilders whose clients may tend to prioritize sustainability systems and structures and net carbon zero home operations, goes back to an origin story rooted in engineering problem-solving and a passion for and expertise in policy development aimed at addressing the growing risks of climate collapse.

Harvest has received numerous awards including being named to TIME’s Top GreenTech Company 2024 list and as a finalist for Reuters Global Energy Transition 2024 award. Harvest has raised nearly $11 million including support from the National Science Foundation, the California Energy Commission, Peninsula Clean Energy, Venture funds, and private investors.

Here's a curated excerpt of a conversation Pierre Delforge had with The Builder's Daily on what led him and his wife Jane to the development of Harvest Thermal, where the fledgling platform is today, and where it may be headed as a broadly applicable home solution.

Computer Programming to Climate Policy

I spent the first 20 years of my career in the computer industry, and ended up with Hewlett-Packard, doing no technology. I wasn't a computer designer, but I was working in the technology field on systems development, doing program management on computer systems in the technology industry. In the mid-2000s, there started to be more visibility and awareness around the climate problem, and as I started to learn about it, I wanted to orient my work towards this area.

Within H-P, I was able to get a position to manage the climate strategy for HP. That was in 2007, '08, and '09. Then, I had an opportunity to do something similar for NRDC. The National Resources Defense Council is a nonprofit advocacy organization that does policy work. I moved from industry to the policy advocacy side, focused on the computer data center, energy efficiency, sustainability, etc. While there, I participated in a big study on how to get to 2050 climate goals in all the sectors of the economy.

One sector being overlooked – where we had no good answer and no active policy initiatives – was using fossil fuels in buildings to heat our homes. That's about 10% of US emissions. About two-thirds of that figure – 62% – comes from home energy use. AC is only about 10% of home energy use in the US. Heating and hot water make up 62%, and we did not have a pathway to decarbonize that. That's how, within NRDC, I started an initiative on building decarbonization – policies to help drive decarbonization policies in the built environment and in homes especially."

The Connection: Where Policy and Engineering Meet

From 2015 to 2022, I led the building decarbonization group, working on building codes and energy efficiency policies, both at the state and federal level. We worked to understand the policy levers that will help move the industry and home users in that direction. They include markets, purchase behaviors, technology offerings, etc. We explored what policy drivers – from incentives and regulations, codes, legislation, etc. – could transform a market shift, a market from its current or previous behaviors, which were largely based on using natural gas. We wanted to put in place the right policy drivers to get the industry to move from using furnaces, gas furnaces, and water heaters to using clean technology, clean energy, which is largely electricity, getting progressively cleaner as we deploy more renewable energy. One of the initiatives I worked on was using water heaters as a thermal storage device. Water heaters have a tank, and by virtue of having a tank, we can use them as a thermal battery for water heating. When I was doing that, I realized that this concept could be extended to space heating, and that's when we had the idea.

Now the CEO of Harvest and a co-founder is my wife, Jane. She's got the business background. She's been in clean energy startups. She's got a lot of connections and experience with clean energy startups. I came with a more technical engineering understanding and a policy understanding of space. We decided to create a company. Harvest is essentially a computer and storage with a heat pump. It's taking a heat pump that does what it does – but not very smartly and without storage – and by adding storage and the smart computer technology, software, and a modern machine learning form of AI, we were able to bring the heat pumps to the next level. That's heat pump 2.0, if we can call it that. This way they're much more suited to the needs of the buildings, of the grid, and reduce people's bills and energy costs."

Early Harvest

We developed the first prototype in 2018 in our own home to prove the concept and ensure it worked. We founded the company in 2019 based on a successful prototype and the promise it showed of being able to make a successful product. We had some grant funding to do several other prototypes and pilot projects. We did a handful of pilot project grants from 2020 to 2021. We launched commercially at a small scale in 2022, and since then, we've sold over 200 systems and we've been expanding.

So our initial market, our launch market, was the San Francisco Bay Area because it's local, and it was a very favorable region in terms of both incentives and customer interest, as well as a critical mass population, with 8 million people. We've started to expand up and down the West Coast, and we are also talking to East Coast utilities in the Northeast, in particular, New York, Massachusetts, and Vermont, or with on doing pilots that are more focused on local climates for colder climates, we've developed with deploy systems in Canada. So we're expanding geographically as well, and we've been developing the product to make it much more scalable, have higher capacity, and be interoperable with more products like the KB Home pilot."

Forward Focus

We're focusing on three major market segments. New construction is one of them, but it also needs a lot of development because production home builders need standardized solutions, and they want proven solutions. You have to start small and build over time. So that's what we're doing. We started with KB and will continue building by working with custom home builders. They can adopt these technologies faster because they tend to be driven by high-performance needs and customer requirements. We provide one of the highest-performance HVAC solutions on the market today, with higher incentives and at a lower cost because of the higher incentives and tax credits that we can take advantage of.

Another segment focus is home retrofits, both single-family home retrofits. We work directly with HVAC contractors and distributors to go to that market. That's our bread and butter today and where we got started. Most of our customers are single-family homeowners, owner-occupied.

The third segment that we're working on is multi-family, particularly large properties—not necessarily high buildings, but garden-style apartments and low-rise properties. Eden Housing, which owns 12,000 rental units in California, for example, has properties with 200 to 400 units. We're currently working on a pilot with them to retrofit one of these properties.

The Value Proposition

Opportunities for this system are multifaceted. It is one of the most sustainable systems on the market in terms of energy efficiency and emissions reduction. Achieving ENERGY STAR Zero Energy Ready certification provides marketing benefits and a competitive edge for builders. Additionally, it offers resiliency benefits due to its storage capacity, providing hot water for multiple days during power outages. This is particularly important in regions prone to wildfires, grid stress, and extreme weather events. From a cost perspective, builders can access more tax credits and incentives with this system compared to a standard system. Buyers of homes with this system can expect lower energy costs due to the load-shifting thermal battery, reducing heating and hot water costs by around 20 to 30% compared to standard heat pumps. This not only offers a sustainability advantage but also adds marketing value by promoting lower energy costs for homeowners."