Naturally, we’d like to help, if only so we can enjoy the series for several more years. Our solution? Let’s weatherize Downton Abbey so it stays toasty warm in winter, reduces heating costs, and saves energy.

To help with our theoretical energy makeover, we enlisted the public relations folks at the real 16th-century Highclere Castle — the setting for the television series — to help with our calculations.

How big is Highclere?

The first thing we noticed is that Highclere is big — really big! — with about 80 bedrooms and more than 120,000 square feet total living area. Energy savings on this little hacienda are going to be impressive.

Of course, so are costs for the energy upgrades we want install. But, like television, it’s all a bit of fantasy.

Energy-efficient widow replacements

“I’m an American; I don’t share your English hatred of comfort.” — Cora Crawley

Highclere Castle has 300 windows. That’s good for increasing daylighting for the interior, but bad for sealing in heat. So let’s change out that old, handmade, single-pane glass for modern double-pane windows.

Cost: According to the Cost vs. Value Report from Remodeling magazine, replacing an old window with a new energy-efficient, wood replacement window costs a national average of $1,680. We’re using the “upscale” cost factor rather than the “mid-range” because, well, it’s Downton Abbey!

Average replacement cost per window: $1,680

No. of windows: 300

Total cost of window replacement: $504,000

We didn’t figure a volume discount here, thinking that any discount would be offset by the fact that Highclere’s windows are larger and more elaborate compared with the straightforward, 3-by-5-foot double-hung windows of our calculations; true replacements would cost considerably more.

Energy savings: According to the energy calculator at England’s Glass and Glazing Federation, the castle would save $274 (that’s £169 for you true fans) per window per year, or a whopping $82,200!

Those windows will pay for themselves in just 7 years. Your welcome, Lord and Lady Grantham.

Changing the fireplaces to fireplace inserts

“O, heavens, girl. You’re building a fire, not inventing it.” — Mrs. Hughes

There are 35 main fireplaces in Highclere Castle, and they all need constant attention and plenty of seasoned firewood to heat up the manor during the colder months. Once we change out those open hearths for energy-efficient, wood-burning fireplace inserts, however, the castle residents will be toastier than a freshly baked Shepherd’s pie.

Cost: An insert costs $3,000 to $4,000 with installation; we’ll settle for an average of $3,500.

Avg. insert cost: $3,500

Number of inserts: 35

Total cost: $122,500

Energy savings: Let’s use the energy-saving figure of about $255 per unit per year, based on a fuel-efficiency calculator from the Hearth, Patio & Barbecue Association. That means an annual energy cost savings of about $7,000.

That’s a lengthy payback period of 17.5 years. But for a house that’s 400 years old and counting, that’s not too bad!

Insulating the castle walls

Lady Rosamund Painswick: “There’s nothing like an English summer, is there?”
Lady Mary Crawley: “Except an English winter.”

The walls of Highclere Castle are made of brick and stone, and are about 30 inches thick. Just for fun, we’ll imagine that there’s a 4-inch-wide hollow space in the walls, enough to let us blow in some cellulose wall insulation.

Using the R-value charts from ColoradoEnergy.org, we’ll say the masonry castle walls have an insulating value of R-5. The empty air space brings it to a total of about R-6.

Blowing cellulose into the castle walls adds R-15, for a total of R-21 — exactly what the U.S. Department of Energy currently recommends for the exterior walls of new homes.

But let’s not forget that what really rocks energy savings is sealing up air leaks. (If you own a castle, you might have to employ a full-time caulker, but us regular home owners can do the job in a couple of hours. A tube of exterior latex caulk is $4; you’ll need 4-6 tubes.)

Cost: It costs at least $1.25 per square foot to add blown-in cellulose, but we’re going to figure a premium for getting through those thick stone walls. Our good-natured insulation contractor is charging us only $2 per square foot. Tally-ho!

Blown-in cellulose insulation: $2 per square foot.

Total exterior wall area: About 3.7 million square feet, accounting for 35% as windows and doors.

Cost of insulating walls: $7.4 million

Energy savings: According to EnergyStar, insulating a drafty house can shave 10% off your utility bills. During the Downton Abbey time period of the early 1900s, the castle was heated with wood, so we’ll use wood heat in our calculations.

Number of fireplaces: 35

Avg. number of cords used per year, per fireplace: 10

Average cost per cord: $250, delivered and stacked

Total energy cost per year: $87,500

Insulating the walls saves 10% of the total, or $8,750 per year. So the payback period for insulating the walls is about 846 years. We suggest lots of wool sweaters and socks instead!