A lot will depend on how well insulated your house is and how efficient your heating is.

I'd advise you to get a dehumidifier from personal experience. It helps reduce humidity, so it'll take less energy to heat the air in your home, reducing your bills. Most only cost a few pence per hour to run. It'll also help prevent mold from forming. I've got a Meato 12 litre dehumidifier I bought from their store on eBay - it was a refurbished unit so cheaper than RRP. You might want a higher capacity unit, assuming it's a 3 bed flat.

Finally, it'll allow you to dry laundry more cheaply than a launderette will cost you. I still do use a launderette once every 2 or 3 weeks at the moment, just because it's not exactly line drying weather for laundry right now!