Energy Drains?

We moved into our new house just under 3 months ago...

When we moved in the house had been vacant for 2 weeks - but apart from 3 - every single light globe in the house was blown ...all the energy saving kind....

So we replaced all the globes to the tune of $100 :rolleyes:

A week later the smoke detector in the lounge started beeping so replaced it with a longlife battery designed for smoke detectors.

A couple of weeks after that the smoke detector in the hall started too - so replaced the battery there. :doh:

In 3 months we have replacd another 7 light globes - all brand new ones we put in when we first moved in - all energy saving ones....my dad is a sparky and we're not getting any electricity surges so it's not that....

Then 4 nights ago the smoke detector started beeping again WTF? Battery was flat.....after 2 months????

Then last night the smoke detector in the lounge was beeping too...

Here is the weird bit (apart from 2 batteries bought at different times giving up the ghost after 8 weeks when they are designed to last for 12mths...)
The smoke detectors ONLY BEEP AT NIGHT.... not during that day at all.....ever....
We actually did an experiement with it and all day it was silent ....it's quiet up until about 11ish then it starts beeping until the sun comes up...then stops again...

*insert X files music*

Now I love our house - it's got a great vibe ....my mum hates our spare room where she sleeps and I have to admit I don't choose to spend a lot of time up that end of the house...
But I have never been freaked out in this place and if there is something around it will usually find me :redface::doh:

I just don't know - what do you think?
Is it just a big coincidence and do I have an overactive imagination or is there something up?

ETA: Forgot to add *sleep deprived brain* it is thought that if there is any spiritual activity that they draw of electrical sources....