The explosions rocked the Mill Street of Lisburn around 2.20 am this morning.
A third device, which had failed to explode, was examined by ATO and made safe.
Chief Inspector David Nixon said: “Thankfully no one was injured however the blasts caused damage to the front of the house and it appears as though a car parked outside the property was also tampered with and damaged.
“A number of residents who were evacuated from nearby homes are being accommodated in the city’s Island Centre.
“The cordon area has been reduced to the Mill Street area and people are asked to remain away from this area while officers conduct enquiries into the incident.
“Anyone with information should contact police on 101, quoting reference number 86 27/02/18. “
“Alternatively, information can also be provided to the independent charity Crimestoppers on 0800 555 111 which is 100% anonymous and gives people the power to speak up and stop crime.”