In the nascent connected home industry, startups now have the choice to tie up with platforms from either Apple AAPL +0.00% or Google GOOGL -0.30%. And going with Apple can make a big difference — that’s at least according to smart thermostat-maker Ecobee.

In July, the Toronto, Canada-based startup released a version of its $250 Ecobee3 thermostat certified by Apple to work with HomeKit, the iPhone maker’s program for syncing up smart home gadgets in iOS. Becoming a HomeKit-certified device has resulted in a major jump in sales for the company. Retail sales have doubled from August to September and then are expected to triple by October, the company said. And to keep up with sales growth, the company’s employee count has grown 20% since July and is now at 120 employees.

Ecobee wouldn’t say how many units it’s now sold, but it’s clearly doing quite well. In the past year, Ecobee has become the second best selling Internet-connected thermostat in the U.S., with 24% of the market, according to research firm NPD. Around four million smart thermostats units will be sold in the U.S. this year, based on estimates from research outfit Parks Associates, and so that pegs Ecobee at selling close to one million thermostats in 2015. Not bad for such an early market.

From the article "Thermostat Wars: With Help From Apple HomeKit, Ecobee Takes Number Two Place Behind Nest" by Aaron Tilley.