You may request an adjustment to your rent due to mortgage rates having fallen (to record lows).

You may request this any time / whenever the applicable mortgage rate ("Referenzinssatz") used for calculation of your rent _is_ below the mortgage rate fixed in your rental contract, and you _will_ get a response. Adjustment of the Referenzzinsatz implies a change to your rental contract, so everything moves at the pace defined in there (notice periods / notice dates)

Keep in mind that your landlord might raise the rent nevertheless, arguing overall increase in rents etc. People seem to be afraid of asking for a reduction as they seem to be scared of retaliation (cancellation of rental contract and other pains). Your call.

You are located in Zurich, so a link to a web site in German is in order: http://www.referenz-zinssatz.ch/allg...renzzinssatzes

This link has every imaginable detail, including templates for you to send out.

Requesting the adjustment downwards is standard operating practice; it very predictably will go upwards again the moment the Referenzzinssatz moves above the interest rate in your (downward-adjusted) rental contract (landlord will send an adjusted contract - it's just turned sides, but that won't happen for years to come due to the way the Referenzzinssatz is computed).

but my question is, we only started the rental contract 1st August 2016. This was our first contract in Switzerland.

Can we already ask for such reduction or do we need to wait 1 full year?

I'm assuming you've mistyped the 2016 but you meant 2015.
Here is the history of reference interest rate changes:
http://www.bwo.admin.ch/themen/mietr...00285/?lang=de

The latest decrease was June 2nd 2015, so your contract certainly has the current one 1.75%, therefore no right for any decrease.

I noticed the latest interest rate decrease only in February this year and I wrote to my agency asking for a reduction in my rent. I got reply that in July they will change my contract so that from October 2016 on I will pay less. I thought I would get a cash back for the past months but the letter from the agency has just arrived and it looks like I will get nothing... Any chance I will see my money though?

You can only apply changes to the contract at some specific dates (written on the contract itself). You will get the discount at the next of such dates, in your case apparently October, be glad

The rent can change at the notice period time. I'm guessing your next notice date is Oct 2016.

Back on the gist of this topic:
interest rates are slowly increasing.
Is there any rule about landlords to passing on the extra costs to tenants?
Is it up to the discretion of the landlord?

Only if the "Referenzzinssatz" changes a landlord can increase the rent again

And that one might actually continue to go down.

Btw, I finally got my reduction, I might reply with the full story at a later time.

But there's good news -- the renter doesn't have to apply for an increase in rent in such cases; the landlord gives notice of the rental increase, and that's it --you have to pay extra. You can pretty much count on the landlord passing on the increase, whereas the renter has to apply for any decrease in rent due to changes to the Referenzzinssatz, which may or may not be grudgingly given (after various spurious deductions). As we all know, if the renter doesn't apply for a decrease, they don't get one.

Not true. Got several over the past years. Landlord even had to remind me to please accept it and change my money-transfer-order accordingly.

Same here, landlord automatically informed me on the reduction of the rent due to the change of the Referenzzinssatz

Sounds like the other behavior is a lot more common, but good for you!

Apologies if I have missed this in the previous almost 300 posts, but a theoretical question:

If a property is not mortgaged, that is, the landlord owns outright so does not gain or lose with changing interest rates, would the tenant nonetheless have the right to claim a rent reduction when the Referenzzinssatz drops, or the landlord be able to raise rents when it increases?

Check your rental contract. If it mentions a link between your rent and the interest rate then yes, else no.

I disagree with Adrian, the Referenzzinsreduction is in the canton law, it cannot be taken away nor added to, by any contract. usually it is referenced to the Canton bank mortgage rate.

Many apartments are owned by pension funds, they do not have mortgages, but they must still make reductions and increases according to the interest rate changes.

As mentioned earlier, any change will happen on the next date when the apartment contract could be terminated, but you should apply soonest.

Wrong. This link is a compulsory provision of the law, see Art 270a OR + VMWG.

You two are in a tiny minority. Do you share an apartment in Zürich?

Whahaha, no! But it was the same in the previous apartment

Believe me (© Donald Trump), for the vast majority, you need to request a rent reduction or you certainly won't receive one. But you can count on your landlord passing on increases.